Robin McKie, the science editor for The Observer on Sunday is predicting a major row later this month when scientists and health experts in the United Kingdom hold two key meetings to debate the issue of cousin marriage and its impact on health in Britain. (See http://www.guardian.co.uk/science/2008/may/11/genetics.medicalresearch?gusrc=rss&feed=networkfront). This is not the first time that the issue of cousin marriage has hit the headlines in the United Kingdom. In February this year The Guardian reported that government minister Phil Woolas spoke out about the health risks involved when cousins have children together. His comments were seconded by Ann Cryer, the Labour MP for Keighley, who has been a long term critic of cousin marriage and had earlier called for the tradition of first cousin marriages to be stopped. Marriage between first cousins raises the probability of a severe genetic illness from a base rate of about 2 percent to approximately 4 percent. Second cousin marriages raised the probability of a severe genetic illness to about 3 percent.
Cryer’s criticisms of the practice of cousin marriage have been directed squarely at the large British Pakistani community living in her constituency. It appears that 55% or more of British Pakistanis are married to their first cousins. The practice is also common in some other South Asian and Middle Eastern Communities. Nowadays it is rare in Europe (except for parts of Spain) however it was very common in earlier times and some very prominent Europeans were married to their first cousins, including Charles Darwin, Albert Einstein and H. G. Wells, as well as innumerable members of the various European royal families.
While critics of cousin marriage make much of the fact that it raises the risk of a severe genetic illness as a reason to ban cousin marriage, defenders of cousin marriage point out that it is only one of a large number of factors that raise this risk and that the vast majority of children of cousins are perfectly healthy. The increase in risk of genetic illness that results from first cousin marriage is equivalent to the increase in risk that is acquired by a woman delaying childbirth from 30 years of age to 41 years of age. The increase in risk of genetic illness that results from second cousin marriage is equivalent to the increase in risk that is acquired by a woman delaying childbirth from 30 years of age to 35 years of age.
It seems unduly harsh and inconsistent to ban cousin marriage because of the increased risk of genetic illness, when we do not consider banning pregnancy for women in their late 30s or 40s. Nevertheless, it seems like a very good idea to discourage the practice of first and second cousins marrying. Smoking and drinking during pregnancy also increase the risk of genetic illness significantly and these activities are severely discouraged by society at large. The birth of children to close cousins could be discouraged by a variety of measures. The most obvious and in many ways the most necessary is to educate people about the dangers associated with cousin marriage. Other methods that deserve consideration include requiring close cousins who are parents to pick up a share of those costs of supporting genetically-ill children that are currently borne by the state.