and brides’ families are agents. Becker (1981) gives an alternative rationale underlying the existence of dowries and bride prices. He views these transfers as ex-ante compensations for ex-post loss of bargaining power. Building on this theory, Zhang and Chan (1999) argue that dowries have the exclusive property of increasing a wife’s bargaining power by raising her threat point. This view however does not explain why such transfers should be taking place at the time of marriage, rather than later on during married life. Moreover, all of these papers remain entirely silent on the subject of consanguineous marriage.

The social science literature on dowries far exceeds that on consanguineous marriages. To partially offset this imbalance, we review important facts and fi ndings related to consanguinity in Section 2. We present our model in Section 3, and Section 4 uses data from Bangladesh to test the main predictions of the theory. Section 5 concludes.

# 2 Consanguineous Marriages

In the fi eld of clinical genetics, a consanguineous marriage is de fi ned as “a union between a couple related as second cousins or closer, equivalent to a coefficient of inbreeding in their progeny of F ≥ 0.0156” (Bittles, 2001).<sup>2</sup> This means that children of such marriages are predicted to inherit copies of identical genes from each parent, which are 1.56 percent of all gene loci over and above the baseline level of homozygosity in the population at large; the closer the parents, the larger the coefficient of inbreeding. A common concern is that consanguinity leads to higher levels of mortality, morbidity and congenital malformations in offspring due to the greater probability of inheriting a recessive gene (Schull, 1959, and Bittles, 1994). According to Bittles (2001), the highest level of inbreeding has been recorded in the South Indian city of Pondicherry, in which 54.9 percent of marriages were consanguineous, corresponding to a mean coefficient of inbreeding of 0.0449, considered very high by the standards of other populations. The existing research on consanguinity also shows that different kinds of consanguineous unions are favoured by different sub-populations: for example, while Hindu women in South India typically marry their maternal uncles, Muslim populations favour fi rst-cousin marriages (Iyer, 2002).<sup>3</sup> Amongst immigrant populations in the UK, those of Pakistani origin display a preponderance of consanguineous marriage, estimated to be as high as 50 to 60 percent of all marriages in this community (Modell, 1991).

Historically in Europe, consanguineous marriage was prevalent until the 20th century, and was associated with royalty and land-owning families (Bittles, 1994). During the 19th and 20th centuries, consanguinity was practised more in the Roman Catholic countries of southern Europe than their northern European Protestant counterparts (McCollough and O’Rourke, 1986). Since the 16th century in England, marriage between fi rst cousins has been considered legal. The Marriage Act of 1949 laid down the kinds of marriage by affinity which are considered void, and this was modi fi ed by the Marriage (Prohibited Degrees of Relationship) Act of 1986. But close-kin marriages are not always legally permitted elsewhere. For example, in the United States, different states have rulings on unions between fi rst cousins: in some states such unions are regarded as illegal; others go so

> <u>2</u> The coefficient of inbreeding is the probability that two homologous alleles in an individual are identical by descent from a recent common ancestor.

> 3 In South India, until the 1950s bridewealth rather than dowry was the preferred marriage system, and in West Bengal as well this was the preferred wealth transfer at the time of marriage. We are grateful to Alan Bittles for highlighting this point to us.

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