Cumulative Effects of Maternal Age and Unintended Pregnancy on Offspring Aggression

Abstract

Research on physical aggression often points to teen motherhood as being a primary contributor in the development of aggressive tendencies among young children. As a result of poor parenting practices, limited education, and a lack of emotional, physical, and financial resources, children born to young mothers often exhibit high levels of aggression across the life course. Meanwhile, unintentional pregnancy and young motherhood are likely to share many of the same risk factors and negative consequences for offspring, yet there is a dearth of research examining pregnancy intentionality and offspring aggression. Using the Fragile Families and Wellbeing Study, our study examines how mother’s age and pregnancy intention status influence aggression among their 5-year-old children. We find that young motherhood and unintended births, despite being likely to co-occur, each provide distinct mechanisms for the formation of aggressive behavior in childhood.

Keywords

attachment criminology pregnancy intention childhood aggression

Introduction

Research on early initiation of aggression has focused on the demographic characteristics and poor parenting practices of mothers as primary contributors to aggressive behavior in early childhood (Côté, Vaillancourt, LeBlanc, Nagin, & Tremblay, 2006; Luster & Mittelstaedt, 1993). In particular, research has identified teenage pregnancy as a crucial risk factor that may contribute to aggressive behavior, as children born to young mothers are less likely to develop adequate self-control and are more likely to experience poor social relationships (Nagin, Farrington, & Pogarski, 1997). Similarly, there are a number of negative health, behavioral, and social consequences for children who result from unintended pregnancies (Barber, Axinn, & Thornton, 1999; Santelli et al., 2003; Joyce, Kaestner, & Korenman, 2000). However, while young motherhood and unintentional pregnancy are likely to co-occur (Finer & Henshaw, 2006), researchers have yet to consider the way in which these factors may be jointly or uniquely related to offspring aggressive behavior in childhood. We bridge this gap by examining the association between young motherhood, pregnancy intention, and early childhood aggressive behavior.

It has been well established that use of physical aggression throughout early childhood is a normal stage of human development (Tremblay et al., 1999). For most, physical aggression emerges during infancy, typically around the first birthday, increases sharply in frequency during the second year of life, peaking around age three, and then decreasing dramatically around the fourth birthday (Tremblay, 2006; Tremblay et al., 1999). It is during this time that most individuals begin to regulate their use of physical aggression by learning more socially accepted, alternative behaviors from their parents (Côté et al., 2006). While a majority of children follow this trajectory, a small percentage (3%-6%) fail to learn how to regulate their aggression, placing them at greater risk for continuing aggressive behavior and physical violence into adulthood (Côté et al., 2006; Tremblay, 2006; Tremblay, Vitaro, Nagin, Pagani, & Séguin, 2003). Frequent and persistent use of aggressive behavior beyond early childhood is predictive of poor educational attainment, involvement in delinquent activities, and failed relationships (Rubin, Hastings, Chen, Stewart, & McNichol, 1998).

Research suggests that prenatal and early postnatal environments greatly influence the child’s development of physical aggression (Tremblay, 2004). As a result, past research on childhood aggression and low self-control has focused on maternal characteristics, in particular examining young mothers (Nagin et al., 1997). The younger a mother is when her child is born, the more adverse outcomes that child is likely to endure (Tremblay, 2004; Nagin et al., 1997). Young mothers are often ill prepared both emotionally and physically to deal with an infant (Geronimus, Korenman, & Hillemeier, 1994). Young mothers are also more likely to spank their children and are less able to provide a stable, nurturing environment for the child (MacKenzie, Nicklas, Brooks-Gunn, & Waldfogel, 2011; Taylor, Manganello, Lee, & Rice, 2010), which may, in part, be due to the limited personal and monetary resources, in addition to a lack of parenting skills that are often associated with young motherhood (Daly & Wilson, 1988). In turn, such characteristic are likely to have a negative impact on the mother’s attachment to her child, a crucial element for the development of self-control (Gottfredson & Hirschi, 1990). Other maternal risk factors associated with chronic physical aggression among offspring include the following: history of antisocial behavior, initiating childbearing at an early age, low levels of educational attainment, living in poverty, and prenatal smoking (Côté et al., 2006; Tremblay et al., 2003). Moreover, these same maternal risk factors are associated with poor maternal parenting skills, which is also predictive of increased aggression (Tremblay et al., 2003).

Parallel to the young motherhood literature, past literature on unplanned pregnancies has examined problems in interpersonal relationships, psychological and behavioral problems, and health problems for both mother and child that may be associated with unintended pregnancies (Barber et al., 1999; Santelli et al., 2003). Having an unintended pregnancy has been found to hinder mother–child relationships, as the additional burden created by an unplanned birth may breed feelings of resentment and anger (Mercer, 2006). Furthermore, greater negative emotionality in mothers with unplanned pregnancies often translates into negative behaviors directed toward the child, which may include abuse and neglect (Joyce et al., 2000). While the literature on pregnancy intentionality has largely found strong relationships between unintended pregnancy and negative maternal interactions and psychological well-being, the impact these detrimental relationships may have on the unintended child as he or she grows older, in particular its influence on aggressive behavior, has received limited empirical attention.

Unintended pregnancies and young motherhood often result from strikingly similar risk factors and contexts that may lead to similar negative consequences for mother and child (Barber et al., 1999; Korenman, Kaestner, & Joyce, 2000; Santelli et al., 2003). Both young and unintended mothers are more likely than other mothers to drop out of school, live in poverty, become depressed after giving birth, and rely on public assistance (Barber et al., 1999; Maynard, 1997). Similarly, children born unintentionally, like those born to young mothers, often receive inadequate prenatal care, limited cognitive stimulation, and have lower birth weight, as well as an increased risk for delinquency during adolescence (Luster & Mittelstaedt, 1993; Moore, Morrison, & Greene, 1997; Nagin et al., 1997).

Although early and unintended pregnancies share many of the same maternal risk factors and potential risks for negative child outcomes, analyses focusing on early and unplanned pregnancies simultaneously have yet to be done. We draw on Gottfredson and Hirschi (1990) in bringing these separate literatures together. Parenting practices such as adequate monitoring, identification of problem behaviors, and proper discipline, utilized during the very first years of a child’s life, are vital to the development of the child’s self-control (Gottfredson & Hirschi, 1990). Inadequate parenting early in a child’s life, characterized by parents’ failure to properly engage in any one of these parenting practices, can result in a failure to develop proper self-control (Gottfredson & Hirschi, 1990).

To adequately monitor, identify, and punish deviant and aggressive behaviors, parents must first form a bond with their child (Gottfredson & Hirschi, 1990). Thus, the parent–child relationship provides the motivation for parents to engage in their parental responsibilities. When the parent is attached to the child, he or she is assumed to have invested in the child’s well-being, and is therefore more willing to monitor, identify, and punish bad behavior. While attachment to a child is hypothesized to be the driving force behind parental behavior, few studies have tested the bond dimension of Gottfredson and Hirschi’s (1990) theory. Thus, prior research has predominantly focused on parental monitoring and punishment styles, largely assuming or accepting a priori that parents develop a bond with the child (Burt, Simons, & Simons, 2006; Nofziger, 2008). Yet it is likely that variation exists in parent–child levels of attachment. Young mothers are more likely to be ill prepared both emotionally and physically to deal with an infant, may be less able to provide a nurturing environment, and may be less able to adequately develop a close parent–child bond (Geronimus et al., 1994; Moore et al., 1997). Similarly, mothers of children born unintentionally may feel greater resentment or stress, may be less involved or invested in, and may be less likely to properly bond or become attached to a child that results from an unintended pregnancy (Barber et al., 1999; Egeland & Farber, 1984; Mercer, 2006). As indicated by Daly and Wilson’s (1980) notion of “discriminative parental solicitude,” mothers who do not develop an attachment within the first few days of the child’s birth often report feeling emotionally detached from that child (p. 281). Thus, maternal resentment, stress, and other external factors may serve as indicators of mother–child relationships that may be problematic or deficient and may ultimately result in negative consequences for the child.

The young motherhood literature has focused primarily on adverse outcomes for offspring, in particular negative behavioral outcomes (Hardy, Astone, Brooks-Gunn, Shapiro, & Miller, 1998; Moore et al., 1997), yet has given little attention to potential problems associated with the maternal emotional attachment to the child. In contrast, past literature on unplanned pregnancies has examined the influence of intention status on the mother–child bond and other adverse social, emotional, and health consequences for mother and child (Barber et al., 1999; Joyce et al., 2000; Santelli et al., 2003), yet the impact of intention status on negative behavioral outcomes has largely been ignored. In the present study, we first examine the joint impact of young motherhood and unintended pregnancy on offspring aggressive behavior. Second, we examine two potential mediating pathways, via maternal resentment and maternal involvement, by which young motherhood and pregnancy intention may influence offspring aggression.

Method

Sample

The current study utilizes data from Fragile Families and Child Wellbeing Study, which is a nationally based sample of 4,898 U.S. children born between the years of 1998 and 2000 from 18 large urban areas. Unmarried parents were oversampled in the data collection process to better understand family processes and child development within “fragile” families. Four waves of data are available, including the baseline interview (time of the focal child’s birth) and when the child was aged 1, 3, and 5 (Bendheim-Thoman Center, 2008). Two interviews were conducted with the primary caregiver when the child was 3 and 5 years of age. This includes a core interview and an interview conducted with a subsample of caregivers for the additional In-Home Longitudinal Study of Preschool-Aged Children. Only biological mothers identified as the primary caregiver are included in the current study. Questions about child aggression and maternal resentment were included in the latter interview. The current study utilizes both the core and In-Home Longitudinal Study, including data from the baseline interview and when the child was 3 and 5 years of age. Upon list-wise deletion on the primary independent and dependent variables, the resulting sample size is 2,691.

Measures

Offspring aggression

We measure child aggressive behavior at age 5, to tap a point in development when most children would have learned to regulate their aggressive tendencies. Following the research of Taylor et al. (2010), our offspring aggression measure is assessed using 12 items from the Child Behavior Checklist when the child was 5, as reported by the mother during the in-home assessment. These questions asked whether the child argues a lot; is cruel, bullies, and shows meanness to others; destroys his or her own things; destroys things belonging to family members or others; is disobedient at home; is disobedient at school or in child care; gets in many fights; physically attacks people; screams a lot; tease a lot; threatens people; or is usually loud. Response options were not true (score of 0), somewhat or sometimes true (score of 1), or very true or often true (score of 2). Because the variable was highly skewed, responses for each item were logged and summated with higher scores indicating greater aggressive behavior. Aggression ranges from −0.69 to 3.20 with a mean of 1.305. (α = .821)

Unintended pregnancy

Following Perreira and Cortes’ (2006) analysis, unintended pregnancy is measured using the question “When you [the mother] found out you were pregnant, did you think about having an abortion?” Asking a parent about whether or not they contemplated abortion may invoke a less socially desirable response; furthermore, some individuals are morally opposed to abortion. Therefore, this measure provides a relatively conservative estimate of pregnancy intentionality. The unintended pregnancy variable is dichotomized, with 1 indicating that the mother had an unintended pregnancy and 0 indicating that the pregnancy was intended.

Maternal age at birth

Mother’s age is a marker of numerous factors related to ineffective parenting. Mother’s age, measured at the time of the focal child’s birth, is a continuous variable ranging from 15 to 45.

Focal child’s sex

Past research has indicated that males are at greater risk than females of developing aggressive tendencies at an early age (Rubin et al., 1998), as a result sex of the child is controlled for in the multivariate analyses. The focal child’s sex is a constructed variable that was identified by the interviewer at Wave 1. Males are coded 1 while females are coded as 0.

Maternal resentment

The present study focuses on maternal attitudes and behaviors directed toward the child. While a primary interest of this study involves the mother’s attachment to her child, there is no direct measure of attachment in the Fragile Families study. Therefore, a measure of maternal resentment is utilized instead as a way to capture the negative components of the attachment spectrum. Mothers were asked a variety of questions assessing their feelings of parental stress ranging from the difficulties of fulfilling parental responsibilities to being unable to do new things since the child was born. The eight items are reverse coded, standardized, and summed to form a composite measure of maternal resentment directed toward the child, with higher scores indicating greater maternal resentment. To increase the confidence of casual order, maternal resentment is measured when the child was age 3, temporally prior to the measurement of child aggression at age 5. The scale’s range is between −15.72 and 10.42. (α = .773)

Maternal involvement

We measure maternal involvement at Wave 3, when the child is age 3. Mothers were asked how many days of the week (0-7) they engage in the following 13 activities with her child: sing songs or nursery rhymes, tell the child they appreciate something he or she did, hug or show physical affection, tell the child he or she is loved, let child help with chores, play imaginary games, read stories, tell stories, play inside, take child to visit relatives, take child out to eat, assist child with eating, and put the child to bed. Responses to the above 13 items were summated together to create the involvement scale, with higher scores indicating more involvement with the child, resulting in a range between 0 and 91 (α = .665).

Maternal race/ethnicity

Maternal race is based on self-identification. Each race, non-Hispanic White, non-Hispanic Black, Hispanic, and Other, is dichotomized, with 1 being the focus race and 0 as all other races. Due to small representation, the three categories, Asian/Pacific Islanders, American Indian/Eskimos, and all other races, were combined to form an “Other” category. Non-Hispanic Whites is the contrast group for the multivariate analyses.

Maternal education

Maternal education is coded into a series of dichotomous dummy variables to reflect the following educational attainment categories: (a) no high school degree; (b) high school diploma or GED; (c) some college, 2-year degree, or technical/trade school; and (d) bachelor’s degree or graduate or professional school. College graduate serves as the contrast category.

Financial assistance

When the child was 3 years old, mothers were asked if they had received welfare, food stamps, or other financial assistance in the past 12 months. This variable was dichotomized, with 1 indicating that yes, the mother received some form of government assistance and 0 indicating that no, the mother did not receive any government assistance.

Maternal relationship status

In general, children who do not reside with both biological parents exhibit higher rates of aggression compared to those who live with both parents (Waldfogel, Craigie, & Brooks-Gunn, 2010). As a result, we created dummy variables for four relationship types: (a) married to biological father, (b) cohabiting with biological father, (c) living with new partner, and (d) single. Married to biological father serves as the contrast category in the multivariate analyses.

Other children

Furthermore, we include a control for the presence of other siblings in the household when the child was 3 years old. The presence of other children may place an additional burden on a mother. Also, prior research suggests that the presence of older children is associated with higher levels of aggression among younger siblings (Tremblay et al., 2003). Children whose mothers had other biological children living in the same household as the focal child when the child was 3 years old are flagged as having other children.

Maternal depression

Maternal depression is found to be one of the most important factors determining a mother’s inability to show sensitivity and responsiveness to her child (Mercer, 2006). As a result, we control for maternal depression when the child was 3 years of age. Mothers who reported feeling depressed for two or more weeks in the past 12 months are coded as 1 and non-depressed mothers are coded 0.

Prenatal substance use

Teen mothers and those who become pregnant unintentionally are more likely to engage in prenatal substance use (Wright & Beaver, 2005). Furthermore, prenatal substance use hinders child development, thereby placing the child at greater risk of aggressive behavior. Measured at the baseline interview, when the child was first born, women who reported using cigarettes, alcohol or illicit drugs at some point during their pregnancy are coded 1, while those who did not engage in prenatal substance use are coded 0.

Mother’s use of spanking

Past research indicates physical punishment is associated with a variety of negative outcomes for the child including anxiety, delinquency, antisocial behavior, and decreased quality of parent–child relationships (Slade & Wissow, 2004). Therefore, spanking is measured when the child was 3 years old. Mothers who spanked their children for “misbehaving or acting up” are coded as 1, those who did not spank are coded as 0.

Mother’s self-control

Critics of socialization research suggest that the correlation between parental behaviors and child outcomes may be a result of genetics rather than parenting (Harris, 1995; Rowe, 1994). While the current data do not have direct genetic measures, there are ample questions measuring the mother’s self-control. As a result, this study also controls for maternal self-control when the child was 3 years of age. The following measures were summated together to create a self-control scale, with higher scores indicating higher self-control: “I will often say whatever comes into my head without thinking first; I often make up my mind without taking the time to consider the situation from all angles; often, I don’t think before I act; I often get into trouble because I don’t think before I act; I often say and do things without considering the consequences; many times, the plans I make don’t work out because I haven’t gone over them carefully enough in advance.” Maternal self-control scale ranges from 6 to 24 with an alpha of .83.

Results

Descriptive Statistics and Bivariate Comparisons

We provide means and proportions for all study variables in Table 1. Overall, 28% of mothers contemplated having an abortion when they found out they were pregnant with the focal child. Consistent with other Fragile Families studies, on average, mothers are approximately 25 years of age. More than half the sample is African American, 64% have a high school education or less, and 65% reported receiving some form of government financial assistance when the focal child was 3 years old. One in four mothers reported prenatal substance use and more than half of mothers spank their child. Furthermore, 61% of the focal children had at least one additional sibling when they were age 3.

Table 1.

Descriptive (Mean/Proportions) and Bivariate Statistical Analyses of Maternal and Focal Child Characteristics According to Pregnancy Intention Status.

	Total Sample (n = 2,691)	Intended Child (n = 1,941)	Unintended Child (n = 750)	p Value
Offspring aggression (logged)	1.305	1.274	1.385	<.01
Unintended pregnancy	0.280	—	—	—
Mother’s age at birth	25.133	25.461	24.291	<.001
Focal child’s sex (female)	0.520	0.525	0.505	ns
Resentment scale	−0.411	−0.721	0.385	<.001
Involvement scale	64.979	65.461	63.732	<.001
Mother’s race
White	0.217	0.260	0.107	<.001
African American	0.504	0.434	0.700	<.001
Hispanic	0.243	0.273	0.168	<.001
Other^a	0.032	0.034	0.028	ns
Mother’s education
Less than high school	0.375	0.363	0.404	ns
High school graduate	0.262	0.250	0.295	<.01
Some college	0.253	0.252	0.254	ns
College graduate	0.109	0.135	0.042	<.001
Financial assistance	0.646	0.560	0.867	<.001
Mother’s relationship status
Married to child’s father	0.304	0.366	0.146	<.001
Cohabiting with child’s father	0.200	0.197	0.206	ns
Cohabiting with or married to new partner	0.092	0.076	0.133	<.001
Single	0.252	0.236	0.291	<.001
Other children	0.617	0.285	0.715	<.001
Mother’s depression	0.245	0.222	0.306	<.001
Prenatal substance use	0.256	0.217	0.353	<.001
Mother’s use of spanking	0.540	0.519	0.594	<.001
Mother’s self-control	17.831	17.915	17.616	<.05

Note. N = 2,691.

Other race includes Asian, American Indian, Eskimo, and Pacific Islander

p < .05. **p < .01. ***p < .001.

To examine the relationship between unintended pregnancy and key variables, we also provide results from bivariate analyses in Table 1. Children resulting from an unintended pregnancy were significantly more aggressive at age 5. Mothers who had an unintended pregnancy were also significantly younger at time of the focal child’s birth. Meanwhile, mothers who had an unintended pregnancy were significantly more resentful of and less involved with their child. Unintended mothers were also more likely to be African American and have lower levels of education. Furthermore, unintended mothers were more likely to receive financial assistance, cohabit with a new partner or be single, be depressed, have other children, use drugs during pregnancy, spank their child, and have lower self-control.

Multivariate Analysis

Having an unintended pregnancy, described in detail in the “Methods” section, is used as the primary independent variable in the multivariate analysis, while offspring aggression serves as the primary dependent variable. Pregnancy intention status may influence childhood aggression indirectly through the mother’s emotionality and behavior; as a result, two mediating variables are proposed in this study: maternal resentment and maternal involvement. Because offspring aggression is linear, ordinary least squares (OLS) regression models are used to predict logged offspring aggression when the child was 5 years of age.

Regression analyses were conducted to examine whether pregnancy intention status predicts offspring aggression at age 5. As shown in Table 2, simple linear regression results (see Model 1) confirm that having an unintended pregnancy does predict offspring aggression (b = .108, SE_b = .04, p = .006). Reported aggression is 11%¹ higher among children resulting from an unintended pregnancy than those who were born as a result of an intended pregnancy.

Table 2.

Coefficients From OLS Regression Predicting Offspring Aggression at Age 5.

	Model 1	Model 2	Model 3	Model 4	Model 5
Unintended pregnancy	0.108**	0.092*	0.082*	0.050	−0.014
Unintended pregnancy	0.040	0.040	0.039	0.039	0.040
Mother’s age at birth		−0.013***	−0.013***	−0.013***	−0.014***
Mother’s age at birth		0.003	0.003	0.003	0.004
Focal child’s sex (female)			0.157***	0.149***	0.140***
Focal child’s sex (female)			0.035	0.035	0.034
Resentment scale				0.031***	0.021***
				0.004	0.004
Involvement scale				−0.005***	−0.004**
				0.001	0.004
Mother’s race (White)
African American					−0.122*
African American					0.050
Hispanic					−0.020
					0.055
Other					0.009
					0.102
Mother’s education (college graduate)
Less than high school					−0.031
Less than high school					0.074
High school graduate					0.035
High school graduate					0.071
Some college					0.048
					0.068
Financial assistance					0.084***
Financial assistance					0.068
Mother’s relationship status (married to father)
Cohabiting with child’s father					−0.013
Cohabiting with child’s father					0.053
Cohabiting with or married to new partner					0.033
Cohabiting with or married to new partner					0.070
Single					0.054
					0.048
Other children					0.165***
					0.039
Mother’s depression					0.034
Mother’s depression					0.533
Prenatal substance use					0.147***
Prenatal substance use					0.042
Mother’s use of spanking					0.238***
Mother’s use of spanking					0.035
Mother’s self-control					−0.020***
Mother’s self-control					0.005
Constant	1.278***	1.604***	1.522***	1.888***	1.929***
R ²	.003	.010	.017	.053	.098
Adjusted R²	.002	.009	.016	.051	.092

Note. Bold numbers are standard errors. N = 2,691. OLS = ordinary least squares.

p < .05. **p < .01. ***p < .001.

In Model 2, we include maternal age at child’s birth to examine if mother’s age would account for the association between pregnancy intention status and offspring aggression. While the unintended pregnancy coefficient is partially reduced, the effect remains significant, in that pregnancy intention status is positively associated with aggression among 5-year-old children. Meanwhile, an additional year increase in maternal age at the time of birth is associated with a decrease in reported offspring childhood aggression, controlling for pregnancy intention status.

Given that males exhibit higher aggression compared with females, Model 3 includes the child’s sex. Similar to Model 2, upon controlling for the offspring’s sex, the effect of pregnancy intention status is reduced but remains significant. Maternal age continues to be significantly and negatively related to offspring aggression. Furthermore, males are significantly more aggressive than females at age 5, controlling for pregnancy intention status and maternal age.²

In Model 4, we see that maternal resentment and maternal involvement are each independently associated with offspring aggression, despite controlling for each other, pregnancy intention, maternal age, and child’s sex. An increase in resentment is associated with higher aggression, while greater maternal involvement is associated with lower offspring aggression. The coefficient for pregnancy intention is reduced to non-significance upon the inclusion of maternal resentment and involvement in the model, presumably indicating a mediation effect. In contrast, the coefficients for maternal age and child’s sex do not substantively change.

In the final model (Model 5), the remainder of the controls are included. Model 5 shows that maternal age remains negatively associated with offspring aggression, despite controls, while the coefficient for pregnancy intention remains non-significant. Furthermore, maternal resentment and maternal involvement remain significantly associated with offspring aggression in the expected directions.

Mediation Analysis

To better understand the pathways by which maternal resentment and involvement may mediate the effects of pregnancy intention on offspring aggression, we employ K. J. Preacher and Hayes’ (2008a) multiple mediation analysis. It was predicted that maternal resentment and involvement would mediate the relationship between pregnancy intention status and offspring aggression 5 years postpartum. Multiple mediation analysis as described by K. J. Preacher and Hayes (2008a) allows us to model the indirect effects of two or more mediating variables simultaneously.

This analysis was completed using the SPSS macro developed by K. L. Preacher and Hayes (2008b). This program uses a bootstrapping resampling strategy to evaluate the significance of the model and mediator effects. The model included unintended pregnancy as the independent variable, offspring aggression at age 5 as the dependent variable, and both maternal resentment and involvement as the mediating variables (see Figure 1). Coefficients indicating relationships between pregnancy intention status, maternal resentment, maternal involvement, and offspring aggression were computed. In addition, the total effect (sum of direct and mediated effects); the direct effect (effect of the independent variable minus the effects of the mediating variables); and the significance levels of total, direct, and specific indirect (mediating variables) effects were calculated.

Figure 1.

Results of mediational model showing associations among unintended pregnancy, the proposed mediating variables (maternal resentment and maternal involvement), and offspring aggression.

Results indicate that both maternal resentment and involvement function as a mediator between pregnancy intention status and offspring aggression. The coefficient for the total effect (sum of the direct effect and the indirect effects) was significant (b = .108, SE_b = .04, t = 2.724, p = .006). However, the test for the direct effect of pregnancy intention status (with mediated indirect effects removed) was not significant, providing additional evidence for the mediation analysis. Coefficients for relationships among independent, mediating, and dependent variables are displayed in Figure 1.

Tests of specific indirect effects were completed using the Sobel test, in additional to confidence intervals (CI) produced by the bootstrapping analysis. Results show that the total indirect and direct effects for both maternal resentment and involvement were significant. Results for indirect effects are displayed in Table 3. The overall model was significant (R² = .0388), F(3, 2,688) = 36.14, p < .001).

Table 3.

Results for Tests of Indirect Effects in Mediation Model.

		Product of Coefficient Tests (Sobel Test)			Bootstrapping (95% Confidence Intervals)
Indirect Effect	Point Estimate	SE	Z	p Value	Lower	Upper
Total	0.044	0.009	5.023	.000	0.028	0.063
Resentment	0.036	0.008	4.542	.000	0.021	0.052
Involvement	0.008	0.004	2.292	.022	0.003	0.017

Discussion

A majority of unintended children are born to young mothers. Furthermore, risk factors and negative consequences associated with unintended pregnancies and young motherhood overlap considerably, yet research has not previously examined the joint impact of young motherhood and unintended conception on offspring aggressive behavior. We find mothers who had an unintended pregnancy are younger on average than those without an unintended pregnancy. Furthermore, children resulting from an unintended pregnancy are more aggressive than those from an intended pregnancy, as are children born to young mothers. However, these effects are not multiplicative, instead pregnancy intention and maternal age are each independently related to offspring aggression.³ This finding suggests that young motherhood and unintended births, despite being likely to co-occur, each provide distinct mechanisms for the formation of aggressive behavior in childhood.

To identify the pathways by which maternal resentment and involvement may account for the effects of pregnancy intention status and maternal age on offspring childhood aggression, we employed K. J. Preacher and Hayes’ (2008a) multiple mediation analysis. Feelings of resentment are associated with more offspring aggression, while greater mother–child involvement is associated with lower levels of offspring aggression, on average. Each partially attenuates the relationship between pregnancy intention and offspring childhood aggression. We find that including maternal resentment and involvement in the model together reduces the influence of pregnancy intention on child’s aggression to non-significance. In contrast, controlling for maternal resentment and maternal involvement has no impact on the relationship between maternal age and offspring aggression in childhood. Childhood aggression is higher among children of younger mothers, regardless of levels of maternal resentment or maternal involvement with the child. Furthermore, in these analyses, contrary to prior research (Geronimus et al., 1994; Hotz, McElroy, & Sanders, 2005), controlling for maternal demographic characteristics does not eliminate the relationship between maternal age and offspring aggression in childhood. Among the present high risk sample, young motherhood is a key predictor of offspring aggression, regardless other maternal demographic characteristics. Thus, we identify multiple pathways, direct and indirect, by which pregnancy intention status and maternal age may influence offspring childhood aggression.

Concern for children of young mothers has received considerable attention and rightfully so. However, we have identified a unique contribution of pregnancy intention on offspring aggressive behavior. Unintended pregnancy is a key risk for offspring aggression in early childhood. Mothers voice greater resentment toward their unintended children, regardless of their involvement with the child. In addition, maternal resentment is associated with lower levels of involvement with the child and higher levels of offspring aggression. The formation of an appropriate parent–child bond is critical for psychosocial development, as weak attachment has been associated with myriad mental health problems (Barber et al., 1999). Similarly, the parent–child bond is critical for the development of self-control and proper socialization (Gottfredson & Hirschi, 1990, p. 98); however, this element of parent–child relationship has been largely ignored in favor of parent–child involvement. We find that resentment has a distinct and direct impact on childhood aggression controlling for mother–child involvement. Furthermore, maternal resentment is inter-related with mother–child involvement, yet each has a distinct effect on offspring aggression. The importance of the parent–child bond for socialization has largely been ignored within the criminological literature, yet the parent–child bond has theoretical and empirical importance as we identify variation in maternal feelings of resentment toward offspring which is linked with subsequent variation in offspring childhood aggression. We also identify a key risk factor for a weakened parent–child bond, in the form of pregnancy intention status.

Despite its contributions to our understanding of childhood aggression in the context of early pregnancy factors, the study has some limitations. First, because we are not able to control for all possible variables associated with early aggression, we cannot rule out the possibility that other factors may be influencing the child’s use of aggression. While we controlled for a variety of demographic factors, it is possible that there are other factors contributing to the child’s aggression, including witnessing violence in the home or in the neighborhood. Second, research examining unintended pregnancies grapple with how to measure intention status. The current analysis measures unintended pregnancy by asking if the mother has thought about having an abortion upon conception. It is possible that additional women in the study had an unintended pregnancy, yet did not consider abortion. Therefore, using this measure captured the most extreme cases of unintended pregnancies. As a result, the measure of unintended pregnancies is likely to be under-reported within this sample.

Third, our aggression measure may be seen as a considerable limitation given its relative ambiguity and subjectivity. Questions regarding the child’s behavior did not ask who the aggressive acts are directed toward, such questions merely asked if the child engaged in fighting or cruel behaviors. But regardless of who the aggressiveness is directed toward, any form of aggression after the age of 4 is a key indicator of future aggressive and criminal behavior. Furthermore, we were unable to account for potential genetic factors that may influence the mother’s behaviors and the child’s aggressiveness. Prior research has shown that antisocial behavior is hereditary, and by failing to account for such genetic factors, it is possible that our models may have produced biased estimates. While we accounted for the mother’s self-control, a potentially major source of bias, it is not possible to control for all potential sources of bias. In addition, although Fragile Families data are longitudinal, caution still needs to be used when drawing casual inferences. Attempts to increase the confidence of casual order were taken in this analysis through using maternal measures at age 3 and child behavioral measures at age 5; however, casual order is still not definite. Finally, the sample is limited to births that occur in large U.S. cities and therefore these results may not be generalizable to births in other contexts.

Nonetheless, the present findings provide considerations for policy implications. We find risks for aggressive behavior not only among children of young mothers but also children who have resulted from unintended pregnancy and of resentful mothers, regardless of age. Interventions targeting young mothers are likely to miss other at-risk mothers, and thus their offspring. In addition, interventions that focus on parent–child involvement miss a key component of the parent–child relationship. Our findings suggest that interventions that focus on the affective component of the mother–child bond, reducing resentment and strengthening maternal feelings toward the child, may have a dual payoff via direct reductions in offspring aggression and indirect effects via increases in mother–child involvement. As identified by Tremblay and colleagues (2004), intervention programs that target infants at greatest risk for aggression would be more effective than programs directed toward school-aged children, when aggression has become normalized. Thus, policies that strengthen the mother–child bond among at-risk families during the early years of the child’s life may have stronger and longer lasting impact on offspring aggression by targeting affective and behavioral components of the parent–child bond.

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The Fragile Families and Child Wellbeing Study was supported by Grant Number R01HD36916 from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). The contents of the paper are solely the responsibility of the authors and do not necessarily represent the official views of the NICHD. This research was supported in part by the Center for Family and Demographic Research, Bowling Green State University, which has core funding from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (R24HD050959-07).

Notes

Author Biographies

Julia M. Mack is an assistant professor in the Department of Criminal Justice at Gannon University. Her research interests center on the effects of teen and unintended pregnancies, peer and relationship factors influencing crime and aggressive behavior, and the association between early criminal justice contact, and future life course outcomes such as romantic unions, maturation levels, and later criminal offending.

Jorge M. Chavez is an associate professor in the Department of Sociology at Bowling Green State University. His research interests center on life course perspectives on child maltreatment and adult outcomes, race/ethnicity differences in the comorbidity of mental health problems and violent behavior, and understanding development and change in violence within community contexts. His recent published research has examined immigration and violent crime, the intergenerational transmission of intimate partner violence, and the temporal and spatial dynamics of urban violence.

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