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.
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.
In the last five years alone up to 60 pairs of twins have been born - with the rate of twins increasing year-on-year.
Local doctor and twin enthusiast Dr Krishnan Sribiju has been studying the medical marvel of Kodinhi for the past two years.
Although 220 sets of twins have been officially registered in the village Dr Sribiju believes the real number to be far higher.
'In my medical opinion there are around 300 to 350 twins within the village boundaries of Kodinhi,' he said.
'What is fascinating is the increasing numbers of twins with each passing year, so much so that I feel in the past ten years the number of twins in Kodinhi has doubled.'
According to villagers, the twin phenomenon only started occurring three generations ago. Dr Sribiju can barely contain his excitement discussing the possible scientific implications of the village.
'To the best of my knowledge this medical marvel began somewhere between 60 to 70 years ago.
'Without access to detailed biochemical analysis equipment I cannot say for certain what the reason for the twinning is, but I feel that it is something to do with what the villagers eat and drink.
'If that is the case then maybe whatever is causing this exceptional level of twinning can be bottled and provide help for infertile couples.' Categorising the twin phenomenon as a naturally occurring anomaly, Dr Sribiju has ruled out genetic factors as the cause due to the localised nature of the village.
He also dismisses any suggestion that the unusual level of twins could be caused by an unknown pollutant pointing to the high number of healthy twins born without any deformities.
'There are lots of reasons for twins, but let me explain the underlying uniqueness of Kodinhi,' said Dr Sribiju, 40.
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'The number of twins per thousand here is around 45 per 1,000 births.
'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 thousand.
'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.
'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.'
The residents of Kodinhi, which is in the lush state of Kerala in the south of India, have even taken to calling their home 'twin town' and have gone as far as to set up the Twins and Kin Association (TAKA).
'TAKA has been set up to register and provide support for the twins of Kodinhi and their families,' said Puallani Bhaskaran, 50, the association's president and the proud father of twin boys.
'Understandably for such a significant minority in the community we feel that it is only sensible to club together to make sure that there is a focal point for the twins of Kodinhi to come to.
'Twins are financially a strain and also they are medically complicated for mothers to bear.
'TAKA can educate and support the villagers because here we have so many more twins than elsewhere.'
Counting more than 220 pairs of twins ranging from 65 years to one month as registered members - with another 30 applications pending - TAKA's total membership exceeds 600 when parents are included.
'I began planning for this association in July 2008 and formalised it in December of last year,' said Mr Bhaskaran.
'The twins of Kodinhi should be united so that they can find out why they are here.' However, for the twins of Kodinhi, life is lived with double takes and stares which eventually become common place.
'When I was at primary school I attended with around 30-40 other twins,' said Anu Bhaskaran, 16, who is the son of TAKA's president.
'It feels special to be part of something so unique, but the most satisfying thing about being a twin is tricking your friends and teachers,' said his brother Abhi.
With the majority of twins in Kodinhi being of the identical kind and the fact that a large percentage are under the age of twenty, the potential for mischief is enormous.
'We always find the teachers mix us up,' said five-year-old Shahala, who attends the local primary school in Kodinhi.
'Sometimes when we are feeling naughty we try and swap classes to confuse people,' said sister Shahana.
Citing the immense scientific implications should Kodinhi's secret be discovered, Dr Sribiju is currently trying to assemble the research support he needs to delve deeper into the twin town of Kodinhi.