It is almost two decades since doctors at Sydney’s Auburn Hospital began to research a devastating pattern of birth defects among babies born to Lebanese families. Led by pioneering obstetrician Dr Caroline de Costa, the study showed significant increases in birth defects, stillbirths and miscarriages among women who were married to blood relatives, particularly first from families who came and second cousins largely, but not exclusively from the Middle East.
Later in the article:
For most in the West, consanguinity is abhorrent but across the world it is a respected cultural practice. Globally at least, 20 per cent of people live in places where cousin-to-cousin marriage is preferred, and nearly 10 per cent of people have consanguineous parents. It is accepted in South-East Asia, Japan, Brazil and Africa, and is particularly common in the Middle East among Muslims and Christians. In Kuwait, Saudi Arabia and Pakistan, about half of all marriages are consanguineous while in Lebanon it is about 25 per cent.
One would think that this practice among such folks would decline after they come to the West. Sadly, their mistrust of the outside / infidel world leads to more marriages within the family.
There are no figures on how widespread inter-family marriage is in Australia, but among immigrant communities in Britain and Canada the practice is even more common than in their country of origin. Researchers say the trend is the same here. Families want to continue cultural traditions, and the small pool of potential spouses makes intermarriage more likely.
So, if you Brits and Canadians see a Pakistani couple in your neighborhood, then it is likely that they're cousins.