For years so many twins were born in the southern Brazilian village of Cândido Godói, the residents wondered whether there was something in the water.
Over the years many theories have been put forward for why this phenomena was occurring – the most popular of which was that Josef Mengele, the Nazi physician known as the Angel of Death, conducted experiments on the women there.
Mengele was a Nazi doctor who conducted twin "studies" in Germany and experiments with twins in Auschwitz, and he was known to have fled to South America as the Allies were closing in on the Nazi German regime.
The Argentine historian Jorge Camarasa suggested that Mengele conducted experiments on women in the area, which could be responsible for the high ratio of twins. Apparently around the time of Mengele's arrival in southern Brazil in 1963, the incidence of twins began to increase, leading to the current rate of twinning of 1 in 10, over half of whom are fraternal twins.
However in 2011, a group of scientists told The New York Times, that they could now rule out that possibility.
Ursula Matte, a geneticist in Porto Alegre, Brazil, said a series of DNA tests conducted on about 30 families since 2009 found that a specific gene in the population of Cândido Godói appears more frequently in mothers of twins than in those without. The phenomenon is compounded by a high level of inbreeding among the population, which is composed almost entirely of German-speaking immigrants.