There's a group of people called the Yoruba who have 40-50 sets of twins for every 1,000 live births! It's believed to be because of a chemical in the yams they eat.
If you've never heard of the Yoruba people, you should have!  They have 45-50 twin sets per 1000 live births and they believe this is all due to the consumption of a certain yam that contains estrogen.
twins are such an interesting subject!what can you tell me about them They're two offspring from the same pregnancy. Would you like to know more? yeah! what type of twins are there? Well, you can have identical which means the egg splits, or you can have fraternal where there are two separate eggs. ohh interesting. what else can you tell me about twins? There are actually people in the world that are non-related look alikes - they are called doppelgangers. ive always wanted to find my doppleganger and hang out for one day lol! what else can you tell me In Central Africa, they have 18-30 sets of twins for every 1,000 live births! wow... that can cause trouble even though it sounds cool lol. any other facts most people dont know?
The Yoruba peoples have the highest rate of twinning in the world, at 45–50 twin sets (or 90–100 twins) per 1,000 live births, possibly because of high consumption of a specific type of yam containing a natural phytoestrogen which may stimulate the ovaries to release an egg from each side.