Question: is it true that if your father is a twin he passes the twin gene down to you?

Hi Lainie, thanks for asking this question again, it has given me a chance to do a little reading on it. It turns out that there is a hereditary basis to twinning. So, there are “maternal” (or “identical” or “monozygotic”) twins, which occur when a fertilized egg splits into two early in development. This type of twinning is not hereditary; if you are an identical twin, there is no increased chance that you yourself will have twins. The other type of twins are “fraternal” (or “non-identical” or “dizygotic”) twins, which occur when two separate fertilisation events occur at the same time (ie two sperms fertilise two different eggs). This type of twinning is hereditary, but it is ONLY hereditary on the mother’s side. This is because the chance of fraternal twinning is affected by the number of eggs the mother releases at a time. If you have a combination of genes that favours multiple egg production, then you are more likely to have twins. As far as I can find out, the mother can inherit the “twin gene” from either her mother or her father. I hope that makes sense! Again, thanks for asking, I found it really interesting to read about! 🙂