Twins in Kodinhi are surprisingly common Hemis / Alamy Stock Photo

A small village in India is seeing an explosion in the number of twins born – and no one knows why.

Kodinhi, in the southern state of Kerala, now has one thousand twins in a population of eleven thousand and the twin birth rate is still increasing. “It’s out of this world,” says Lorena Madrigal of the University of South Florida.

The background rate of twin births in India is about one in a hundred, so the twin numbers in Kodinhi stand out.

The phenomenon came to global attention …