Seeing Double: In This Village, 1 in 5 Births Results in Twins

Baffled doctors are trying to unravel the mystery of an Indian village boasting more than 220 sets of twins born to just 2,000 families.

The twins from the remote tropical village of Kodinhi, in Kerala

Experts who have visited the remote tropical village of Kodinhi, in Kerala, have been left scratching their heads over the phenomenon that has seen almost six times as many twins born than the global average.

In 2008 alone, 15 pairs of twins were born in the village out of 300 healthy deliveries and this year is expected to top that number.

Local doctor and twin enthusiast Dr Krishnan Sribiju has been studying the medical marvel of Kodinhi for the past two years and is fascinated.

"The number of twins per thousand here is around 45 per 1,000 births," he said.

"Indian, and by that I mean Asian, people on the sub-continent have the lowest acknowledged incidences of twinning in the world at around four per 1,000.

"In addition, there is no IVF treatment here because of the prohibitive cost. Global rates of twins being born, especially in the western world, have increased because of artificial insemination.

Identical twins are a "fluke"

"Also, twins are born usually to older, more mature women. In Kodinhi that is not the case because marriage happens much younger here at around 18-20 years-old and families begin very soon after.

"Another factor that bucks the trend is that twins occur in women who are generally over 5ft 3in in height. The height of women in Kodinhi is around 5ft on average."

Even though identical twins are considered a fluke, the village has its share of those too.

Debbie Ross, from Tamba, a charity that specialises in twins and multiple births, told Sky News Online the unusual births could be due to a number of factors.

"Usually, there's about a one in 65 chance of having non-identical twins, with the chances lessening the older the mother gets," she explained.

In the case of this particular village, Ms Ross suggests there could be a hereditary factor at work.

"It may be that many of the families with twins are related in some way - and there is a hereditary factor to twin births - you're more likely to have twins if there is a previous maternal history of it."