I recently came across an interesting article in Little India by Lovejeet Alexander that explores how a small village in India has the highest number of twins compared to anywhere in the world. The village, Mohammadpur Umri, is located near Allahabad at the confluence of the sacred Ganges and Yamuna Rivers. Of the 300 households, there are 54 pairs of twins. As Alexander writes, "... in India there is a 1 chance in 80 for a mother to deliver twins and 1 in 300 for delivering identical twins. In Umri, however, one of ten deliveries result in identical twins... The village boasts a twin monozygotic (MZ) or identical twin birth rate that is 300 times the national average and perhaps the highest in the world."
Scientists, doctors, and the villagers have differing opinions about why there are an unusually high number of twins in a concentrated area. The phenomenon started about 40 years ago at around the same time that an Air Force Base was set near the village. Some believe the station's experimentation machinery causes the twinning. Others believe there is something in the soil and water, or that it is "God's Gift." Perhaps even more fascinating is that Umri also has twin cows and buffaloes, as well as hens that lay eggs with double yolks.
For more on the Umri community, check out the article in its entirety at Little India.