Consanguineous marriage is rare in most Western countries and, for example, in the USA it may be subject to regulation by both civil legislation and religious prescription. This is not the case in many regions of Asia and Africa where marriage within the family is strongly favored. Since the 1970s there has been widespread migration to North America, Western Europe, and Australasia from communities which encourage consanguineous marriage. To assess the effect of this trend on a genetic counseling program, the records of 302 couples referred to Genetic Services of Western Australia for consanguinity counseling were abstracted for the period 1975-2001. Overall, a family history of genetic disease or a previously affected child was reported in 28.8% of cases. Premarital or prepregnancy counseling on grounds of consanguinity was sought by 41.0% of couples, and a further 18.2% of consanguineous couples had been referred because of a consanguineous pregnancy. In 7.6% of cases a relationship closer than first cousin was involved. Through time there was a significant increase in the numbers of consanguineous consultants, and their patterns of religious affiliation and ethnic origin widened markedly. Although effectively excluded from entry to Australia prior to 1975, couples of Asian origin accounted for 25.5% of all consanguineous consultants. With ongoing migration, changes in the ethnic profiles and the specific counseling requirements of consanguineous couples can be expected to continue and probably accelerate.

Objective: To determine the current prevalence of consanguineous marriage in Western Australia, as a means of assessing the associated requirement for genetic counselling services. Subjects and Methods: The records of all intended marriages in Western Australia were examined over a 6-year period (1994–1999), with the numbers and types of consanguineous unions collated and analysed by year, current domicile and countries of origin. Results and Conclusions: Of the 62,549 proposed marriages, 144 (0.23%) were between couples who identified themselves as biological relatives, 82 (0.13%) of whom were first cousins. The mean coefficient of inbreeding α for the total sample was 0.00009. In 75.7% of cases either one or both of the partners had been born outside Australia. Given the patterns of recent migration to Australia, it is suggested that these figures should be treated as minimal estimates of the actual levels of consanguinity in the population.