Sex between cousins can be healthy, says an Australian academic who believes New Zealand may see more unions between family members as immigrants enter the country.
For the past 30 years geneticist Professor Alan Bittles, of the Centre of Comparative Genomics at Murdoch University in Western Australia, has been studying the effects of consanguineous, or same-blood marriages on children.
In New Zealand it is not illegal to marry your cousin.
Bittles said first-cousin marriage was more widespread than many would think and there were misconceptions about the health risks it presented.
“A lot of people marry their cousins. The entire population of the world is around 6.2 billion and one billion people live in countries where 20 to over 50 per cent of marriages are between cousins, 2.9 billion live in countries where it is between 1 per cent and 10 per cent,” Bittles said.
The studies he has carried out on children born of first cousins has shown 75 per cent were healthy.
“In Western culture there is a general belief that first-cousin marriages lead to negative genetic outcomes, yet a large majority of children born to first cousins are healthy,” he said.
“The snag would be if you both inherit some mutant gene. Then your children are much more likely to be affected.”
Problems such as inherited blood disease and some intellectual disabilities have been associated with first-cousin unions.
First-cousin marriage is common in many Muslim countries and Bittles said it could become more prevalent in New Zealand and Australia if immigration from these countries increased.
He recently returned from a conference in London, where high immigration from South Asian and Middle Eastern countries has sparked debate on the safety of cousin marriages.
“My message would be that we need to be much more realistic about our present population,” Bittles said.
He said if cousins were considering marrying but were worried about the effects it might have on their children, they should undergo genetic screening.
Although the numbers of people gaining residency from Muslim dominated countries has gone down, there are an estimated 30,000 followers of Islam in New Zealand.
Federation of Islamic Associations of New Zealand (FIANZ) president Javed Khan said the prevalence of first cousin marriage varied between different Muslim groups. “As the community grows there is more interaction with people outside your immediate family and as a result of that I have rarely come across marriages between cousins,” he said.
Khan agreed the health risks of first cousin marriage were overblown. “It’s more of a myth than a reality. I haven’t come across any incidents of it and no issue has been brought to my notice.”
Jan Sullivan, of Central and Southern Regional Genetic Services in Christchurch, said it was important to genetically screen people.
Marrying cousin not a health risk – geneticist
Meanwhile, for the Pakistani in Britain we have other evidences: