Problems with dating 3rd cousin consolidating debt alberta
Charles Darwin The naturalist, whose work forms the basis for contemporary evolutionary theory, married his first cousin Emma Wedgwood in 1839.
They had 10 children, to whom he was a devoted father.
"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," said Professor Spencer, whose co-authored study is published in the online journal Public Library of Science.
First-cousin marriages were once quite common in Europe, especially among the elite – Charles Darwin married his first cousin Emma Wedgwood – but that changed in the late 19th-century as people, especially women, became more socially mobile and the risks became more evident.
We all carry gene mutations and sometimes, such as in the case of cystic fibrosis, they are fairly common in the general population.
But when a population has a small gene pool the gene mutation can become more frequent.
Some have called for such "consanguineous" marriages to be banned but others argue better genetic screening is what's needed.
Peter Corry of St Luke's Hospital in Bradford estimates that among people of Pakistani descent in the city, 55 per cent of whom marry first cousins, the risk of recessive genetic disorders – the type due to related parents – is between 10 and 15 times higher than in the general population.
A 2004 study found that 13 out of 1,000 Asian children born in the Bradford area had inherited recessive disorders, which can lead to disabilities.
Complex issue Professor Alan Bittles, director for the centre for human genetics in Perth, Australia has collated data on infant mortality in children born within first-cousin marriages from around the world and found that the extra increased risk of death is 1.2%.
In terms of birth defects, he says, the risks rise from about 2% in the general population to 4% when the parents are closely related.
Professor Spencer, an evolutionary zoologist, said these laws should be repealed, especially in America, where he said they were drafted in a way that discriminated against the rural poor and immigrants: "Neither the scientific nor social assumptions behind such legislation stand up to close scrutiny.