An Australian researcher says that consanguineous marriages need not adversely affect the health of the offspring.
Adjunct Professor Alan Bittles from Murdoch's Centre for Comparative Genomics points out, "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.
"A global analysis has shown that early death or major ill-health is on average four to five percent higher in children of first cousins than equivalent non-consanguineous offspring."
Given the global numbers of cousin marriages, Professor Bittles believes comprehensive health-based studies of short and longer-term outcomes are long overdue.
"Simply banning consanguineous marriages, which has been suggested by some opponents in Britain, is simplistic and of limited relevance," Professor Bittles said.
"A more workable approach would be to identify the families in which specific genetic diseases occur, as part of culture-sensitive genetic counselling and premarital carrier testing programmes," he argues.
"Britain has seen a rise in first cousin marriages amongst its Pakistani migrant population which has led to debate about the health outcomes," Professor Bittles said.
Professor Bittles was the lead speaker in a debate in East London on May 29 discussing whether cousin marriages are a cause for concern, according to a press release.
Bittles has spent 30 years researching the effect of consanguineous (or same blood) marriages on health outcomes and intellectual and development disabilities.
He asserts, "There is a widespread misconception that these marriages are rare.
"In reality there are over 1000 million people worldwide that live in regions where 20-50 per cent of marriages are between blood relatives.
"These types of unions are common in many Muslim, Buddhist, Christian, Hindu, and Jewish communities."
He also believes there will be a greater incidence of first cousin marriages in Australia as more migrants from these communities come into the country.
Murdoch PhD candidate Helen Mountain agrees that genetic counselling of first cousin partners is effective.
"Genetic counselling puts the genetic risk into perspective with the general population," Ms Mountain said.
"Often couples realise it's not as high as they thought, and couples at greater risk because of a family history can be identified."
Although genetic counselling has been available in Western Australia for the last 25 years, Ms Mountain said there has been an increase in the number of cousin couples requesting this service over the last 10 years.
"Only 0.5 per cent or about 500 marriages are between first cousins in Western Australia," Ms Mountain said.