Changing Trends of Consanguineous Marriages in South India

Abstract

Consanguineous marriage is still a preferred option in many societies of southern India. Therefore, this study addresses the state and district wise variation in consanguineous marriages and also attempts to find out the underlying factors of this practice in different marriage cohorts of South India. Drawing data from National Family Health Survey-4, the result revealed that there is a reduction in consanguineous marriages from 32.6% who married before 1985 to 23% during 2010–2014. About 13 districts in Tamil Nadu had the highest prevalence of consanguineous marriages, indicating that recent socio-demographic changes such as delays in age at marriages, lesser age gaps between partners, increase in the level of education, etc., did not explicitly affect the consanguineous marriages.

Keywords

Consanguineous marriage marriage cohort mean age at marriage South India

Introduction

About one-fifth of the population living in different parts of the world prefers consanguineous marriages, and at least 8.5% of children are products of these marital unions (Modell and Darr, 2002). Consanguineous marriage is referred to as a marital union between an individual who belongs to the same genealogical kin (Bittles, 2001). However, consanguineous marriage ranges from cross-cousin to more distant relatedness, and the rate at which consanguineous marriages occur in a population depends on the population structure and several other factors such as socio-demographic, economic, linguistic, geographical characteristics, etc. (Campbell et al., 2009). In countries in regions such as North Africa, the Middle East and West Asia where consanguineous marriages are immensely popular they account for 20%–50% of all marriages, with the highest local rates of inbreeding in some specific religious groups, immigrants, etc. (Bittles, 2011), whereas in the Western world consanguineous marriages constitute less than 1% of the total marriages (Bittles, 2001). However, the status of consanguinity has declined in most of the communities of developed and developing countries through time (Krishnamoorthy and Audinarayana, 2001).

Globally, marriages involving first degree (parents–offspring) and second degree (brother–sister) relationships are called incest and considered to be taboo in almost all the cultures around the world (Kuper, 2002). However, first cousin and uncle–niece unions are more frequent, comprising 20%–30% of all marriages (Bittles and Black, 2010). The most likely reasons for the popularity of such practices can be summarized as a strong family tradition of consanguineous unions, maintenance of family structure and property, strengthening of family ties, financial advantages relating to dowry or bridewealth payments, easy marital arrangements, and a closer relationship between the wife and her in-laws and greater marriage stability and durability (Shenk et al., 2016). The degree of social compatibility and close involvement of the entire family lowers the rates of divorces and enhances female autonomy, leading to more consanguineous unions in the community. Additionally, among some population groups where consanguinity is preferential, the highest rates have been associated with low socio-economic status, illiteracy, and rural residence (Hussain and Bittles, 2004). Although endogamy is a type of marriage that is practiced majorly all over India, exogamy and consanguineous marriages are also widespread in some parts (Ray, 2020). This wide variation in the marriage practices and patterns within communities and between states can be explained by the existence of innumerable castes, tribes, and communities in India (Devi and Kumari, 2000). For example, consanguineous marriages are shunned in the northern parts of India, whereas marriage between blood relatives is highly preferred and encouraged in the southern states of India of Dravidian origin as part of the prevailing social customs particularly in the states of Andhra Pradesh, Karnataka, Pondicherry, and Tamil Nadu (Sharma et al., 2020).

The findings from the National Family Health Survey (NFHS)-1 (1992–1993) data brought to light important findings on the consanguineous marriages quite extensively. The findings revealed that in every state, consanguineous marriages were mainly between first cousins (10%) and second cousins (4%), either on the father’s side or on the mother’s side. Uncle–niece marriages were rare in all the states except in Tamil Nadu and Andhra Pradesh (Hussain and Bittles, 2000). The regional differences distinguish Maharashtra and exclude Kerala from the high prevalence of close relative marriages, especially due to the decline of such unions among the long-established Muslim community and the overall decline in the rates among the Hindu community since the 1961 census of India (Hussain and Bittles, 2000).

Results from some distinctive studies negatively correlated inbreeding in south India with socio-economic status (Bittles, 2002a). Determinants such as age, age at marriage, caste, religion, place of residence, education, and economic status are found to be the major confounding factors that affect consanguineous marriages in India. A large number of studies suggest that with an increase in the female level of education, there is a decrease in the consanguineous marriages due to an increase in the probability of finding partners of choice and educational homogamy among partners (Audinarayana and Krishnamoorthy, 2000). Several studies revealed that ethnic groups (Muslims and Hindus), having fewer physical assets, lower social capital, and residing in rural areas showed a higher frequency of consanguineous marriages. Wealth or parent’s financial status at the time of women’s marriage also has a very significant role in the prevalence of consanguineous marriages; for example, Do et al. (2013) have shown a value of the landholding, leading to the incidences of consanguineous marriages increasing with decreasing landholding of the women’s father, in other words, such types of marital unions are more common in the poorer households. Caste and religion are often considered as markers of socio-cultural backgrounds and are expected to influence the beliefs, norms, and values of the population.

Although there are many factors that lead to consanguineous marriages in society, there are certain adverse consequences of inbreeding, such as increasing the potential risk of genetic disorders. However, ironically, consanguineous marriage is prevalent and is still preferred in many societies in southern India. Hence, this study is conducted to understand the underlying socio-economic and other factors of this practice in different periods of South India.

Objectives

The specific objectives of this study are:

(a) To know the trends and patterns of consanguineous marriages in the states of southern India.

(b) To understand the district level variation of consanguineous marriages in the southern states of India.

Data and methods

Data for this study are based on the fourth round of the Indian Demographic and Health Survey, widely known as the NFHS-4, which was carried out in all the states and union territories of the country during 2015–2016. The main objective of the survey is to provide essential data on health and family welfare, as well as data on emerging issues in these areas. Thus, the survey provides information on maternal and child health, fertility, nutrition, contraceptive behaviours, human immunodeficiency virus/acquired immune deficiency syndrome, and other issues. The International Institute for Population Sciences was the nodal agency to carry out the survey under the stewardship of the Ministry of Health and Family Welfare, Government of India, and technical support from ICF International. This is a large scale, multi-round survey conducted in a representative sample of 601,509 households comprising 699,627 women aged 15–49 years and 112,122 men aged 15–54 years. The detailed information on the sample design, sample weight and questionnaire of the survey can be found in the national report (International Institute of Population Sciences and ICF International, 2017).

For the analysis of the present study, data for five states of southern India, that is, Andhra Pradesh, Karnataka, Kerala, Tamil Nadu, and Telangana have been used. A total number of 126,846 ever-married women aged 15–49 years were interviewed in NFHS-4 from these states which became the unit of analysis. As the NFHS provides information on a woman’s relationship with her husband before marriage, the study of consanguineous marriage becomes possible. For defining consanguineous marriage, five categories, namely first cousin on the father’s side, a first cousin on the mother’s side, second cousin, uncle, and other blood relatives were considered. Other categories such as brother-in-law, other non-blood relative and husband not related are categorized as non-consanguineous marriage. Standard statistical methods were applied to understand the changing composition of consanguineous marriage over the 2015–2016 period in South India. As the sample size in NFHS 4 permits to estimate the district level prevalence of consanguineous marriages, district-level variation is examined in the study. From the NFHS data, marriage-year cohorts were identified based on the information of the year of marriage. In cases where the year of marriage is not recorded, date of birth and age at marriage of women is considered to obtain the year of marriage. Covariates included in the study are year of marriage (before 1985, 1985–1994, 1995–2004 and 2005–2014), age at marriage (before age 15, 15–17 and above 18), caste (Scheduled caste, Scheduled tribe, other backward castes (OBC), and others), religion (Hindu, Muslim, and Christian), educational level of women (no education, primary, secondary and higher), wealth index (poorest, poorer, middle, richer and richest), and place of residence (urban and rural). Bivariate analysis and logistic regression analyses were carried out in the study. The mean age at marriage by consanguineous and non-consanguineous marriages has been computed to understand the changes over time.

Results

Trends of consanguineous marriages

Table 1 presents the prevalence of consanguineous marriage by the year of marriage of women. A noticeable reduction in consanguineous marriage was observed among women who got married before 1985 (32.6%) and in the year 2010–2014 (23.4%). A higher proportion of such unions were observed in Tamil Nadu with a substantial decline by the year of marriage of women, except for Andhra Pradesh and Telangana, where the decline was gradual from the year before 1985 to the years between 2010 and 2014. In addition, there was a small increase in consanguineous marriages in Andhra Pradesh during 1995–1999 (Figure 1).

Table 1.

Trends in consanguineous marriages in states of South India.

Year of marriage	Andhra Pradesh	Karnataka	Kerala	Tamil Nadu	Telangana	South India
Before 1985	32.7	31.3	7.2	39.3	28.6	32.6
1985–1989	26.6	23.2	5.2	36.4	25.5	27.1
1990–1994	29.9	27.7	5.7	34.9	25.9	27.7
1995–1999	30.4	25.1	4.7	33.7	28.0	26.6
2000–2004	29.7	25.2	4.3	29.3	23.9	24.4
2005–2009	25.3	25.4	4.4	28.7	23.8	23.7
2010–2014	26.1	24.1	4.5	28.9	20.4	23.4
Decline	6.6	7.2	2.7	10.4	8.2	9.2
Level of significance	***	***		***	***	***

Note: ***: <1% level of significance.

Figure 1.

Trends in consanguineous marriages in states of South India, 1978–2014.

Relation to husband before marriage

Table 2 presents the changing composition of consanguineous marriages in South India over the years according to the type of blood relationship. The results highlighted the changes in the prevalence of consanguineous marriages during four periods of time. The period before 1985 is considered as the first cohort, and the periods 1985–1994, 1995–2004, and 2005–2014, as the second, third and fourth cohort of the change, respectively. The most consanguineous marriages were reduced to first cousins on the father’s side from 14.0% to 10.3% during the second cohort. A similar pattern was observed in the reduction of such unions in Andhra Pradesh, Tamil Nadu, and Telangana where the rate of reduction was about 3% in the second cohort. Yet, this rate of reduction was observed to be very gradual in the third and fourth cohorts in most of the southern states except Andhra Pradesh. The consanguineous marriage to the first cousin on the mother’s side decreased from 13.3% to 11.4% in the second cohort. Though the maximum reduction was noticed in the case of Karnataka (from 17.4% to 12.4%) in the second cohort, the rate increased in the third cohort in states such as Andhra Pradesh (13.6%), Karnataka (12.8%), and Telangana (8.7%), and in the fourth cohort in states such as Karnataka (13.4%) and Kerala (1.5%) which was unexpected, keeping in mind the educational and economic changes in these states. The study found an increase in the prevalence of consanguineous marriage with the second cousin and other blood relatives in the second cohort; however, the prevalence declined gradually over the years. Also, in the second cohort states such as Andhra Pradesh (2.3%), Karnataka (0.3%) and Kerala (0.1%) witnessed a slight increase in the rates of consanguineous marriages with the uncle, in spite of being the most controversial union; however, the prevalence finally declined in the third cohort and fourth cohort in the selected states except for Telangana. Furthermore, the marriage with brother-in-law and other non-blood relatives increased in recent years. A significant increase in marriages with non-related people (64%–70.4%) was observed in the second cohort – for instance, Andhra Pradesh and Karnataka witnessed the highest increase among southern states. Data also revealed that though the prevalence of marriage with non-related people has increased over the years, the rate of increase slowed down compared to the second cohort.

Table 2.

Changing composition of consanguineous marriages by type of blood relationship in the states of South India.

State/year of marriage	First cousin on father’s side	First cousin on mother’s side	Second cousin	Uncle	Other blood relative	Consanguineous	Brother in-law	Other non-blood relative	Not related
Andhra Pradesh	11.6	12.1	0.5	1.9	2.4	28.5	3.3	0.3	67.9
Before 1985	14.1	13.9	0.2	2.0	2.5	32.7	4.9	0.4	61.9
1985–1994	11.0	12.0	0.8	2.3	2.4	28.5	3.9	0.4	67.3
1995–2004	11.6	13.6	0.5	1.9	2.5	30.1	2.9	0.3	66.8
2005–2014	11.4	10.2	0.3	1.4	2.4	25.7	2.9	0.3	71.1
Karnataka	9.1	13.1	1.2	0.3	1.7	25.4	0.3	0.3	74.0
Before 1985	11.8	17.4	0.6	0.2	1.3	31.3	0.1	0.2	68.5
1985–1994	10.3	12.4	1.5	0.3	1.4	25.9	0.4	0.2	73.7
1995–2004	8.6	12.8	1.6	0.3	1.9	25.2	0.3	0.1	74.4
2005–2014	8.5	13.4	0.7	0.3	1.9	24.8	0.2	0.5	74.6
Kerala	1.7	1.4	0.5	0.1	1.1	4.8	0.0	1.1	94.1
Before 1985	2.6	3.0	0.0	0.0	1.5	7.1	0.0	2.3	90.6
1985–1994	2.2	1.5	0.4	0.1	1.3	5.5	0.0	1.0	93.5
1995–2004	1.7	1.2	0.4	0.1	1.0	4.4	0.0	0.9	94.6
2005–2014	1.3	1.5	0.5	0.0	1.1	4.4	0.1	1.4	94.1
Tamil Nadu	10.5	13.2	2.2	3.6	2.7	32.2	0.1	0.8	66.9
Before 1985	14.2	14.8	2.3	4.8	3.1	39.2	0.1	0.5	60.1
1985–1994	11.1	14.9	2.3	4.1	3.2	35.6	0.1	0.8	63.6
1995–2004	10.1	13.3	2.2	3.5	2.4	31.5	0.2	1.0	67.3
2005–2014	9.8	11.6	2.1	2.9	2.4	28.8	0.2	0.7	70.3
Telangana	12.7	8.1	0.5	0.5	2.9	24.7	4.3	1.1	69.8
Before 1985	16.8	9.0	0.3	0.5	1.9	28.5	6.4	0.6	64.5
1985–1994	13.2	8.3	0.4	0.5	3.3	25.7	4.3	1.0	69.0
1995–2004	12.9	8.7	0.6	0.7	3.0	25.9	3.6	1.0	69.5
2005–2014	11.0	7.3	0.6	0.5	2.8	22.2	4.2	1.4	72.3
Southern states	9.7	10.9	1.2	1.7	2.3	25.8	1.4	0.7	72.2
Before 1985	14.0	13.3	0.9	2.1	2.3	32.6	2.9	0.5	64.0
1985–1994	10.3	11.4	1.4	2.0	2.4	27.5	1.5	0.6	70.4
1995–2004	9.3	11.0	1.3	1.7	2.2	25.5	1.2	0.6	72.7
2005–2014	9.0	10.0	1.1	1.4	2.2	23.7	1.3	0.7	74.4

District wise variation in consanguineous marriage in South India

Table 3 presents the prevalence of consanguineous marriages in districts of South India. The prevalence of consanguineous marriages ranged from 42.5% in Ramanathapuram district in Tamil Nadu to 3% in Kannur district in Kerala (Figure 2). In Tamil Nadu and Karnataka, the prevalence of consanguineous marriages in 18 districts, was higher than the state’s average. In Karnataka, Yadgir district accounted for 39.1% of consanguineous marriages. Out of 13 districts in Andhra Pradesh, eight districts had a higher prevalence of consanguineous marriages than the state’s average. In Andhra Pradesh, the prevalence of consanguineous marriage was highly concentrated in the Srikakulam district (36.9%). Nalgonda district (33.5%) in Telangana had the highest concentration of consanguineous marriages. Though Kerala had the lowest prevalence of consanguineous marriages among the southern states, the highest prevalence was found in the Idukki district (8.6%), as shown in Figure 2 .

Table 3.

Prevalence of consanguineous marriage in districts of South India.

District	Percentage	District	Percentage	District	Percentage
Andhra Pradesh		Mandya	22.2	Perambalur	35.6
Srikakulam	36.8	Hassan	21.8	Viluppuram	35.4
Prakasam	31.2	Gulbarga	21.2	Krishnagiri	35.3
Kurnool	30.8	Shimoga	20.5	Virudhunagar	34.4
Krishna	30.6	Uttara Kannada	18.7	Vellore	33.3
Guntur	30.5	Bidar	18.4	Erode	33.3
Anantapur	30.4	Kodagu	14.9	Ariyalur	33.1
Vizianagaram	30.2	Udupi	13.4	Karur	32.3
Chittoor	29.2	Dakshina Kannada	11.8	Dindigul	32.2
Visakhapatnam	28.4	Belgaum	10.0	Coimbatore	31.3
East Godavari	25.3	Kerala		Thoothukkudi	31.2
West Godavari	25.3	Idukki	8.6	Nagapattinam	30.8
Kadapa district	22.6	Palakkad	8.0	The Nilgiris	30.6
Sri Potti Sriramulu Nellore	20.9	Kasaragod	6.3	Thiruvallur	30.5
Karnataka		Thrissur	6.1	Kancheepuram	29.9
Yadgir	39.1	Alappuzha	5.1	Tiruppur	29.7
Gadag	38.0	Wayanad	4.8	Cuddalore	28.9
Bijapur	37.9	Thiruvananthapuram	4.8	Tirunelveli	28.4
Koppal	36.0	Pathanamthitta	4.7	Thanjavur	28.2
Chitradurga	35.6	Malappuram	4.3	Thiruvarur	28.1
Haveri	31.8	Kollam	4.2	Namakkal	26.7
Raichur	30.5	Ernakulam	3.6	Chennai	22.5
Chikkaballapura	29.5	Kottayam	3.6	Kanniyakumari	14.8
Bagalkot	29.2	Kozhikode	3.3	Telangana
Bangalore	29.2	Kannur	3.0	Nalgonda	33.5
Davanagere	28.9	Tamil Nadu		Warangal	33.2
Bangalore Rural	28.1	Ramanathapuram	42.5	Khammam	32.7
Bellary	26.9	Theni	41.0	Adilabad	31.8
Tumkur	26.7	Madurai	40.5	Mahbubnagar	25.7
Chamarajanagar	26.1	Dharmapuri	40.4	Medak	22.6
Kolar	26.0	Salem	39.0	Karimnagar	21.4
Ramanagara	25.8	Tiruvannamalai	37.5	Nizamabad	20.4
Dharwad	25.5	Pudukkottai	37.2	Hyderabad	18.9
Mysore	25.2	Sivaganga	36.9	Rangareddy	18.9
Chikmagalur	24.3	Tiruchirappalli	36.2

Figure 2.

Prevalence of consanguineous marriages in districts of Southern India, National Family Health Survey 4.

Trends in mean age at marriage of women by consanguineous and non-consanguineous marriage

Table 4 presents the trends in the mean age at marriage of women in consanguineous and non-consanguineous marriages in South India from the year 1978–2014. The data revealed that the mean age at marriage among those who had consanguineous marriage was below the legal age at marriage up to 1997. Interestingly, the mean age at marriage of women with consanguineous marriage was higher (11.2 years) in the year 1978, but it remained consistently lower in the following years compared to those in non-consanguineous marriage (Figure 3). An increase in the mean age at marriage is observed in consanguineous marriage, that is, from 11.2 in 1978 to 20.5 in 2014. Similarly, the increase in the mean age at marriage is also observed among those who had gone for non-consanguineous marriage, that is, from 10.9 years in 1978 to 22.1 years in 2014. Though there is an increase in the mean age at marriage in both consanguineous and non-consanguineous marriages, the gap in mean age at marriage in non-consanguineous and consanguineous marriage has widened over the years. It is evident that the mean age at marriage is consistently lower among women who had consanguineous marriage than their non-consanguineous counterparts. It indicates that the ready availability of brides and grooms among blood relatives/consanguineous unions pushes them to marry earlier than the non-consanguineous unions, where searching for suitable partners take time.

Table 4.

Trends in the mean age at marriage of women by consanguinity in South India.

Year of marriage	Consanguineous marriages	Non-consanguineous marriages	Total	Gap between non-consanguineous and consanguineous marriages
1978	11.2	10.9	11.0	−0.3
1979	11.4	11.8	11.7	0.3
1980	12.3	12.4	12.4	0.1
1981	13.0	13.2	13.1	0.2
1982	13.7	13.8	13.8	0.1
1983	14.5	14.5	14.5	0.0
1984	15.0	15.1	15.1	0.1
1985	15.4	15.7	15.6	0.3
1986	15.8	16.2	16.1	0.3
1987	16.2	16.6	16.5	0.5
1988	16.5	17.0	16.8	0.5
1989	16.7	17.3	17.1	0.5
1990	17.0	17.6	17.4	0.6
1991	17.2	17.9	17.7	0.7
1992	17.3	18.2	17.9	0.9
1993	17.4	18.4	18.1	1.0
1994	17.6	18.7	18.4	1.1
1995	17.7	18.9	18.6	1.3
1996	17.8	19.0	18.7	1.2
1997	17.9	19.2	18.8	1.2
1998	18.0	19.2	18.9	1.3
1999	18.1	19.3	19.0	1.2
2000	18.1	19.4	19.0	1.2
2001	18.1	19.5	19.1	1.4
2002	18.2	19.7	19.3	1.4
2003	18.5	19.9	19.6	1.4
2004	18.6	20.1	19.7	1.5
2005	18.8	20.3	19.9	1.5
2006	19.0	20.5	20.1	1.5
2007	19.2	20.7	20.3	1.5
2008	19.4	20.9	20.5	1.5
2009	19.6	21.1	20.8	1.5
2010	19.9	21.3	20.9	1.4
2011	20.1	21.5	21.1	1.3
2012	20.3	21.6	21.3	1.4
2013	20.7	21.7	21.5	1.1
2014	20.5	22.1	21.8	1.6

Note: five-years moving average.

Figure 3.

Trends in the mean age at marriage of women by consanguinity in South India, 1978–2014.

Table 5 presents the mean age at marriage of women by consanguinity in the states of South India. To study the trend in the mean age at marriage of women in consanguineous marriage in five states, four time periods were considered. These included women who got married before 1985, from 1985 to 1994, from 1995 to 2004, and from 2005 to 2014. The results obtained using analysis of variance showed that there is a statistically significant difference between group means. Furthermore, these results showed the different levels and trends of the mean age at marriage in different states, for instance, Andhra Pradesh (16.6 years) had the lowest mean age at marriage of women in consanguineous marriage followed by Telangana (16.8 years). However, the trend shows that the extent of increase of mean age at marriage was more in Telangana (19.1 years) compared to Andhra Pradesh (18.3 years) of women in consanguineous marriage. Interestingly enough, the increase in the mean age at marriage was highest in the case of Kerala where it increased from 14.3 years before 1985 to 21.6 years in 2005–2014, the reason being the average age at which women got married was relatively higher before 1985 in Kerala. The results revealed that women having consanguineous marriages were younger compared to those having non-consanguineous marriages over the years. This pattern was similar for every selected state. Also, the gap between the mean age at marriage of women in non-consanguineous and consanguineous marriage for every selected state widened over the years, perhaps due to a sudden gain in the mean age at marriage of women in non-consanguineous marriage, whereas the mean age at marriage of women in consanguineous marriage remained below the legal age at marriage till the year 2004 for every state except in Kerala (20.8 years) and Tamil Nadu (19.1 years). Overall, Kerala (21.6 years) had the highest mean age at marriage of women in consanguineous marriage, followed by Tamil Nadu (20.6 years).

Table 5.

Mean age at marriage of women by consanguinity in the states of South India.

State/year of marriage	Consanguineous marriages	Non-consanguineous marriages	Total	Gap between non-consanguineous and consanguineous marriage
Andhra Pradesh	16.6	17.7	17.4
Before 1985	13.5	13.9	13.8	0.4
1985–1994	15.8	16.4	16.3	0.6
1995–2004	16.9	17.8	17.5	1.0
2005–2014	18.3	19.6	19.3	1.4
Karnataka	18.0	19.2	18.9
Before 1985	13.4	12.9	13.0	−0.5
1985–1994	16.6	17.3	17.1	0.7
1995–2004	17.8	19.2	18.9	1.4
2005–2014	19.8	21.1	20.8	1.4
Kerala	20.2	21.2	21.1
Before 1985	14.3	14.7	14.6	0.4
1985–1994	18.4	19.5	19.4	1.1
1995–2004	20.8	21.5	21.4	0.7
2005–2014	21.6	22.4	22.4	0.8
Tamil Nadu	18.7	20.0	19.6
Before 1985	13.5	14.0	13.8	0.4
1985–1994	17.6	18.3	18.0	0.7
1995–2004	19.1	20.2	19.8	1.1
2005–2014	20.6	22.0	21.6	1.4
Telangana	16.8	17.6	17.4
Before 1985	12.4	12.0	12.1	−0.4
1985–1994	15.8	15.9	15.9	0.1
1995–2004	16.9	17.6	17.4	0.6
2005–2014	19.1	20.2	19.9	1.1
South India	17.9	19.2	18.8
Before 1985	13.3	13.3	13.3	0.1
1985–1994	16.8	17.5	17.3	0.7
1995–2004	18.0	19.4	19.1	1.4
2005–2014	19.7	21.2	20.8	1.4

Consanguineous marriage by background characteristics

Table 6 presents the percentage of ever-married women age 15–49 who have had consanguineous marriage by background characteristics. It illustrates the variation in the percentage of consanguineous marriage across the selected states due to changes in the socio-economic and demographic status of women. The percentage of ever-married women who had consanguineous marriage has declined over the years, that is, from 32.6% who got married before 1985 to 23.5% who got married during 2005–2014. The prevalence of consanguineous marriage was found to be higher among those who had early age at marriage. Concerning caste, the reported consanguineous marriage was found higher among Schedule tribe (33.1%) followed by Schedule caste (29.5%); this pattern was similar over the years. In the southern states, the consanguineous marriage was higher among Hindus (27.4%) than their Christian (18.4%) and Muslim (17.6%) counterparts. The consanguineous marriages were found to be higher among women who had no education (30%), which was almost double compared to women with higher education (17%). The women belonging to the poorer wealth quintile had the highest percentage (31.4%) of consanguineous marriage in the southern states compared to all other economic categories. Furthermore, the prevalence of consanguineous marriage was found to be higher in rural areas (27.7%) than in urban areas (23.3%) in southern India. This pattern was consistent over the years. It was evident that the decline in consanguineous marriage was more prominent in Tamil Nadu compared to other states of southern India.

Table 6.

Percentage of ever-married women age 15–49 who have had consanguineous marriage by background characteristics, Southern India, National Family Health Survey IV.

Background characteristics	Before 1985	1985–1994	1995–2004	2005–2014	Total
Year of marriage
Before 1985	–	–	–	–	32.6
1985–1994	–	–	–	–	27.5
1995–2004	–	–	–	–	25.5
2005–2014	–	–	–	–	23.5
Age at marriage
<15	32.4	31.8	34.2	41.0	33.2
15–17	31.6	28.8	30.6	31.6	30.4
18 and above	42.9	24.0	20.8	20.9	21.6
Caste
Schedule caste	34.4	29.7	29.9	28.1	29.5
Schedule tribe	39.2	34.9	34.5	29.3	33.1
Other backward castes	32.0	27.8	25.1	23.0	25.5
Others	28.9	21.3	18.6	17.1	19.4
Religion
Hindu	34.2	29.4	27.1	24.7	27.4
Muslim	21.9	17.7	17.5	16.9	17.6
Christian	20.7	14.9	18.9	20.3	18.4
Educational level
No education	34.0	30.0	29.5	26.3	30.0
Primary	29.9	28.7	30.8	24.9	28.7
Secondary	30.2	24.6	24.3	25.4	25.0
Higher	+	21.8	15.0	17.0	17.0
Wealth index
Poorest	34.3	29.2	31.3	28.2	30.0
Poorer	35.9	31.6	31.0	30.5	31.4
Middle	32.4	28.5	28.0	27.0	28.1
Richer	31.1	26.9	24.2	22.2	24.6
Richest	31.7	24.2	19.9	16.9	20.6
Place of residence
Urban	32.1	25.5	22.9	20.7	23.3
Rural	32.8	29.0	27.6	25.9	27.7
State
Andhra Pradesh	32.7	28.4	30.1	25.7	28.5
Karnataka	31.3	25.8	25.2	24.7	25.5
Kerala	7.2	5.5	4.5	4.4	4.8
Tamil Nadu	39.3	35.5	31.6	28.8	32.1
Telangana	28.6	25.7	25.9	22.1	24.8
Total	32.6	27.5	25.5	23.5	25.8

Note: +, secondary and higher education are clubbed together.

Table 7 presents the odds ratios (ORs) of background characteristics for consanguineous marriage at different times in South India. Concerning the period, the likelihood of consanguineous marriage in South India was significantly lower in 2005–2014 than those who got married before 1985. The age at marriage was found to be a strong independent predictor of consanguineous marriage in South India. It was found that the likelihood of consanguineous marriage was significantly lower among women who got married after the age of 15 and above (except those who married before 1985). Consanguineous marriages were more common among Hindus, Scheduled tribe, and the women hailing from rural areas. Regarding caste, these marriages were significantly higher among Scheduled tribe women (OR 1.25) and significantly lower among women belonging to other caste (OR 0.88) and those of Scheduled caste women, which was quite similar for the years of 1995–2004 and 2005–2014. On the other hand, no significant result was found for women who belonged to OBC and other castes who got married before 1985 and during 1985–1994. The consanguineous marriage was significantly lower among Muslims (OR 0.83) and Christians (OR 0.79) than those of Hindu women, yet, no significant result was found for Christian women in the year 2005–2014.

Table 7.

Odds ratios showing the effect of background variables on the consanguineous marriage in South India: results from logistic regression analyses.

Background characteristics	Before 1985	1985–1994	1995–2004	2005–2014	Total
Year of marriage
Before 1985^®
1985–1994	–	–	–	–	0.980
1995–2004	–	–	–	–	0.975
2005–2014	–	–	–	–	0.947*
Age at marriage
<15^®
15–17	0.942	0.869***	0.891***	0.683***	0.907***
18 and above	1.424***	0.724***	0.622***	0.435***	0.644***
Caste
Schedule caste^®
Schedule tribe	1.268*	1.415***	1.294***	1.098*	1.255***
Other backward castes	0.933	1.001	0.921***	0.898***	0.937***
Others	0.891	0.953	0.866***	0.835***	0.881***
Religion
Hindu^®
Muslim	0.759**	0.765***	0.854***	0.908**	0.839***
Christian	0.526***	0.566***	0.869**	0.992	0.796***
Educational level
No education^®
Primary	0.837**	0.983	1.107***	0.930	1.012
Secondary	0.902	1.002	1.041	1.170***	1.070***
Higher	+	0.945	0.688***	0.935	0.798***
Wealth Index
Poorest^®
Poorer	1.093	1.117	1.008	1.125*	1.077**
Middle	0.985	1.064	0.931	1.024	0.996
Richer	0.99	1.135*	0.974	0.964	1.002
Richest	1.098	1.215**	1.062	0.881	1.028
Place of residence
Urban^®
Rural	0.972	1.199***	1.158***	1.129***	1.146***
State
Andhra Pradesh^®
Karnataka	0.908	0.895***	0.844***	1.021	0.915***
Kerala	0.194***	0.182***	0.147***	0.176***	0.165***
Tamil Nadu	1.296***	1.499***	1.233***	1.337***	1.337***
Telangana	0.780***	0.840***	0.814***	0.872***	0.836***
Constant	0.567***	0.380***	0.530***	0.613***	0.481***

Notes: ^®, reference category; +, secondary and higher education are clubbed together; ***, **, *: <1%, 5% and 10% level of significance, respectively.

The study revealed that there is a significant negative association between level of education of women and consanguineous marriage. The odds for women who had secondary education is 1.07 and those who had a higher level of education 0.79 compared to women with no education. The consanguineous marriage was found to be exceptionally higher among women with primary (OR 1.10) level of education in 1995–2004 and secondary level of education (OR 1.17) in 2005–2014. The odds were substantially lower among women with higher level of education than the women with no education.

Controlling the effect of other variables, there is a very weak effect of the wealth index on consanguineous marriage in South India. Furthermore, no significant results were found in all the years except for a few (richer and richest in 1985–1994). Overall, it is widely perceived that consanguineous marriage is more prevalent among the underprivileged sections of society, and the findings of the present study verify these findings. The likelihood of consanguineous marriage was significantly higher in rural areas than urban areas. The results show statistical significance in all the years except before 1985. With reference to Andhra Pradesh, the practice of consanguineous marriage was significantly higher (OR 1.33) in Tamil Nadu and low in Telangana, Karnataka, and Kerala.

Discussion and conclusion

Consanguineous unions account for 25.8% of all marriages in the southern states of India. The findings of the present study clearly indicate the gradual decline in the prevalence of consanguineous marriages in southern India as is the case in other parts of India where preferential unions between blood relatives is a common practice due to factors such as familiarity, socio-economic biases, and behavioural commonalities (Lekshmi and Sudhakaran, 2012). A very low percentage of these unions were observed in Kerala (4.8%), which may be due to higher education and lower economic backwardness, and a decrease in parental influence in marriage decisions compared to other southern states (Joseph et al., 2014). However, the degree at which it is practiced in other southern states and the trends in consanguineous marriage largely shows the prevailing customs and cultural practices in certain communities. Out of all the southern states, Tamil Nadu had the highest levels of consanguineous marriage. Earlier studies suggested that groups such as Latin Catholics, Valans, Jacobite Syrians and Syrian Catholics are the least inbred groups while Malyali Muslims, Nayars and Tamil Brahmans had the highest inbreeding (Ali, 1968). Over the three decades, the highest decline (10.4%) in consanguineous marriage in found in Tamil Nadu compared to other southern states of India. Studies suggested that, the decline in consanguineous marriage began after a post-fertility decline in the 1980s, resulting in smaller family size, upward mobility and change in status under the influence of education and employment. This replaced the kin factor as a key criterion for marriage during that time period (Krishnamoorthy and Audinarayana, 2001).

The most popular forms of consanguineous marriages were with first cousin marriage on the mother’s side (10.9%), followed by the first cousin on the father’s side (9.7%). Uncle–niece marriage was least popular among all unions in the selected states because of the unacceptable age difference between partners (Bittles, 2002b), except for Tamil Nadu, where it still continues (2.9%). Evidence shows that this type of union brings higher risks of genetic defects compared to first cousin marriage (Bhagya et al., 2012; Kumaramanickavel et al., 2002). These small scale studies quite comprehensively establish an association between consanguineous marriage and morbidities among children; for instance, in a study of Belgaum district of Karnataka, consanguineous marriage was found to be significantly associated with 2.5% and 3.3% of higher stillbirths and pregnancy loss. The present study revealed that Belgaum is the district now with least consanguinity (10.0%). Another study on 14 districts of Andhra Pradesh shows that inbreeding caused higher mortality and morbidity compared to those with unrelated parents (Sanghvi, 1982). However, there are still inadequacies in explaining why consanguineous marriage is still an integral part of all the 13 districts of Andhra Pradesh as well as almost every district of Tamil Nadu.

Although, marriage as a social institution has undergone a rapid change, mean age at marriage for women was very low in some regions of India (Jensen and Thornton, 2003) and the Second Amendment of the Child Marriage Restraint Act was passed in the year 1978, whereby the legal minimum age of marriage was increased to 18 and 21 for female and males, respectively (Saxena and Mohanty, 2013). Studies suggested that the effect of the amendment passed in 1978 was observed in the years 1979–1980, specifically in the mean age at marriage of women in consanguineous marriages as daughters were married at a younger age (11.4 and 11.5 years) compared to those in non-consanguineous marriage due to pre-decided alliance between families (Krishnamoorthy and Audinarayana, 2001). Data revealed that the mean age at marriage (11.2–11.5 years) was even lower than the mean age at menarche (13.26 years) during the period 1978–1981 (Bai and Vijayalakshmi, 1978), which was considered as an acceptable time for marriage in many parts of southern India (Pathak et al., 2014). Studies also revealed that the probability of women to get married at younger ages is higher in consanguineous marriage (Hosseini-Chavoshi et al., 2014; Khan and Mazhar, 2018). Another improvement in the mean age at marriage was noticeable after 2006 as it changed from 19.0 to 20.5 years (above legal age at marriage), perhaps due to the Child Marriage Prohibition Act 2006, although this change was observed a decade earlier in the case of women in non-consanguineous marriage (Saxena and Mohanty, 2013).

The analysis indicates that socio-economic and demographic factors play a significant role in the prevalence of consanguineous marriage among women in many districts in the southern states of India. Many groups in India find spousal relationships to be durable by unions among kins or acquaintances, and in modern India, where welfare and safety of women are questionable, the preferred choice then becomes consanguineous marriage (Bittles, 2002b). Our findings suggest that consanguineous marriage is positively correlated with no or lower level of education, the reason being that women are unaware of the serious consequences of consanguineous unions and ignorant about scientific evidence for the higher mortality and morbidity caused by such marriages. On the other hand highly educated women are more aware and have more control over decision-making and choosing their partners (Barbour and Salameh, 2009; Hussain et al., 2000). However, there was a huge regional variation, as districts with a very high level of literacy rates, for instance, Dharmapuri in Tamil Nadu, unexpectedly had a very high prevalence of consanguineous marriages. About 13 districts in Tamil Nadu had the highest prevalence of consanguineous marriages, indicating that the recent demographic and social changes such as delays in age at marriages, lesser age gaps between partners, increase in the level of education, etc. (Audinarayana and Krishnamoorthy, 2000), did not explicitly affect the marriage system in these districts.

Apart from that, studies suggest that consanguineous marriage is mostly practiced in agricultural economies as a “family wealth maximization” strategy where the integration of land holdings of kins reinforces the familial partnerships (Kuper, 2009), which is consistent with our study findings, as the majority of the unions where partners are found to be blood relatives are in the rural areas and among Schedule tribes. Furthermore, a study on three castes of Nellore district in Andhra Pradesh suggests that intra-village marriage is the most common practice among both consanguineous couples and non-consanguineous couples, and the mean matrimonial distance was also found to be lowest (Reddy, 1988). Another economic motivation for consanguineous marriage mentioned in past studies was lack of wealth. Marriage among relatives avoids larger dowry payments at the time of marriage which is an advantage for poor families (Hamamy, 2012), and women belonging to the poor wealth quintile are most likely to get married to a close blood relative as this will keep the family property in the family.

Overall, the study concludes that the higher level of education poses greater autonomy in mate selection which leads to a substantial change in matchmaking. Our findings revealed that higher level of education and increasing age at marriage of women are the prominent reasons for the decline in consanguineous marriages in South India.

Footnotes

Declaration of conflicting interest

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

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

ORCID iDs

Harihar Sahoo

Sathiyasusuman Appunni

Author biographies

Harihar Sahoo is an Associate Professor in the Department of Development Studies at the International Institute for Population Sciences (IIPS), Mumbai. His research interests include fertility, family planning, reproductive and child health, family demography, population and development.

Paramita Debnath is a doctoral candidate in Population Studies at International Institute for Population Sciences, Mumbai, India. Her research interests include ageing, reproductive health and mental health.

Chaitali Mandal is a Senior Project Officer of International Institute for Population Sciences, Mumbai. She has completed M.Phil. in Population Studies from IIPS. Her research interests include gender issues, women and migration and reproductive health.

R. Nagarajan is a Professor in the Department of Development Studies at the International Institute for Population Sciences, Mumbai. His research and teaching interest include population and development, public health, fertility, maternal and child health, gender and population ageing.

Sathiyasusuman Appunni is at the Faculty of Natural Sciences, Dept. of Statistics and Population Studies. His specific research interests are Reproductive and child health, Migration & HIV/AIDS, Contraceptive dynamics, Mortality, Fertility issues, Ageing & retirement, Empowerment of women, Population & Development, Socio-economic inequality, Family Demography, Technical demography, Public Health & Health policy.

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