Marriage between cousins is fine, say scientists
Babies born as a result of marriages between first cousins are at no greater risk than those born to women over 40, a study claims.
By Ben Leach
Last Updated: 12:17PM GMT 24 Dec 2008
Scientists at the University of Massachusetts in Boston have called for the taboo on first-cousin families to be lifted.
They claim that the risk of giving birth to babies with genetic defects is no greater than that run by women over 40 who become pregnant.
First-cousin marriages are legal in the UK but there have been calls to ban the practice because of the number of genetic defects recorded in some communities.
Professor Diane Paul of the University of Massachusetts in Boston and Professor Hamish Spencer of the University of Otago in Dunedin, New Zealand have looked at the risk of defects in such babies.
They claim that the risk of congenital defects is about 2 per cent higher that average, and the infant mortality rate about 4.4 per cent higher, for babies born to first-cousin marriages.
This is on a par with the risk to babies born to women over 40, they claim.
Professor Spencer said: "Women over the age of 40 have a similar risk of having children with birth defects and no one is suggesting they should be prevented from reproducing."
The study is published in the online journal Public Library of Science.
MP Phil Woolas, now the Immigration minister, claimed earlier this year that first-cousin marriages within Asian communities in Britain resulted in an increasing number of children with health problems.
Most states in America have either outlawed or restricted the practice, as has China, Taiwan and both North and South Korea.
Professor Spencer, an evolutionary zoologist, said these laws should be repealed, especially in America, where he said they were drafted in a way that discriminated against the rural poor and immigrants.
He said: "Neither the scientific nor social assumptions behind such legislation stand up to close scrutiny.
"Such legislation reflects outmoded prejudices about immigrants and the rural poor and relies on over-simplified views of heredity.
"There is no scientific grounding for it."