What science has to say about cousin-marriage
In the US, there are 31 state laws that either bar cousin marriage or permit it only where the couple obtains genetic counseling or is beyond reproductive age or if one partner is sterile. Clearly, the western world sees cousin marriage as both socially unacceptable and scientifically wrong.
Science talk
Scientists have heavily criticized both the negative social stigma’s associated with cousin marriage and the incorrect perception of risk involved with child birth.
“Such legislation reflects outmoded prejudices about immigrants and the rural poor and relies on oversimplified views of heredity. There is no scientific grounding for it,” says Professor Hamish Spencer, a Research Associate at Harvard’s Museum of Comparative Zoology. “Neither the scientific nor social assumptions behind such legislation stand up to close scrutiny.”
The risk factor according to NSGC
The US National Society of Genetic Counselors (NSGC) report estimated the average risk as 1.7 – 2 per cent higher than the background population risk of congenital defects and 4.4 per cent higher than general risk for dying in childhood.
“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. People with Huntington’s Disease or other autosomal dominant disorders have a 50 per cent risk of transmitting the underlying genes to offspring and they are not barred either,” Professor Spencer says.
