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

Experts who visit 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. There is no IVF treatment in Kerala because of the prohibitive cost.

Dr. Krishnan Sribiju has been studying the medical marvel of Kodinhi for the past two years.

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

Debbie Ross, from Tamba, a charity that specializes in twins and multiple births, told Sky News online the unusual births could be due to a number of factors, like age of the mother or genetics.

"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," she said.

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