That was the case in the southern Nigerian city of Igbo Ora, where the Festival of Twins has just taken place. More than 1,000 pairs have gathered there from around the world to celebrate their special sibling situation – but why there? Because nearly every family in the city has a set of twins or other multiple births, according to local chief Jimoh Titiloye. The city has more than 200,000 people living in it, so that’s a lot of twins… There’s no accepted scientific evidence for why that’s the case, but locals reckon it has something to do with a local delicacy they eat a lot there called amala, which is made from yam flour. Just flagging that with you in case you’re looking to get up the duff…