Quote:
Originally Posted by Samo the gene would have to come from your mother's side as your mother is the one who would have to ovulate twice  not your father! So this means your mother would have to have passed it to you, so in your case...twins may not be in your genes! |
Just what I was going to say.
Fraternal (non-identical twins) are thought to be hereditary on the mothers side, as having them would mean that your body produced 2 eggs at once.
Identical twins, are thought to be random, and are caused by the spliting of an egg after fertilization - although I think there is a little evidence of certain people being prone to having eggs that split.
Obviously with the advent of IVF more twins are now being born, those children when they grow up will be no more likely to have twins than the rest of us.