Igbo Ora, ( also spelled Igbo-Ora ) Nigeria : the "Twins Capital of the World".
Twins are very common among the Yoruba people, by far the dominant ethnic group in this part of Nigeria. A study done in the 1970s showed that around 50 sets of twins were born out of every 1,000 births in the southwest - one of the highest rates of twin births in the world. But in Igbo Ora, in Oyo State in south west Nigeria, the rate is much higher. In the local high school almost 20% of the students have a twin sibling. In the Yoruba culture twins are so common that they are traditionally given specific names. Traditionally the Yoruba people name their male twins either Taiwo or Kehinde depending on whether they were born first or second. So if you meet a Nigerian named Taiwo, you can be pretty sure that he has a twin brother named Kehinde. Locals believe that the exceptional percentage of twins among them is somehow related to the Okra they eat in their traditional cuisine.