Seeing double: the village in deepest Kerala where twins have taken over

It is the village of the doppelganger. Turn a corner in Kodinhi in rural Kerala, one of India's greenest and richest states, and if you have seen one child you will probably run into its double soon after. In this community of 2,000 families there are 250 sets of twins. In 2008 alone, of the 300 families who had children, 15 pairs were born, a rate at least six times higher than the average for the country. India has one of the lowest twinning rates in the world, but Kodinhi is close to the top of the global twinning league.

Krishnan Sribiju, a doctor at the Tirurangadi Taluk hospital, just outside the village, said the number of twins born was increasing year by year. In the past five years, up to 60 pairs had been born, and the 250 pairs who had been registered understated the true total. The high number of children with indistinguishable features makes life difficult for teachers. Abhi, 16, standing beside his brother, said: "I comb my hair to the right and he combs his hair to the left. I also have a mark on my neck. Apart from these differences there is nothing else."

Dr Sribiju, a dermatologist and public health specialist who has been studying the high twinning rate for nine years, said the cause remained a mystery. In a telephone interview yesterday, he said: "We are working on a hypothesis that it is something in nature, or in the water or the sand. We do not think it is something in the food because they don't have something particular that they eat. There are thousands of heavy metals that could be in the water and affecting the people but it takes a long time to work out. It is very difficult."

He dismissed suggestions that the cause could be the high rate of intermarriage among the predominantly Muslim population. "It is not limited to Muslim families. It is also seen in Hindus and Christians and it does not affect Muslim communities elsewhere. Families that move to the area are also affected after living there for a few years. This is a very small geographical area measuring three to four kilometres. It is likely to be something external not genetic."

Dr Sribiju said he believed most of the twins were non-identical. That meant, he said, that something was affecting the mothers causing them to produce extra eggs. Identical twins develop from a single embryo that splits soon after fertilisation while non-identical twins are the product of separate eggs that have been fertilised at the same time.

via Seeing double: the village in deepest Kerala where twins have taken over - Science, News - The Independent.