With identical, its also the mother's egg that's the deciding factor. You have to either be more likely to ovulate twice (fraternal twins) or have a genetic disposition of having your egg split after fertilization (identical twins).
My husband is a fraternal twin and I was like 90% sure I was carrying twins, but the doctor assured me both times that there's just one. I was measuring bigger because its my second pregnancy. You usually show sooner after the first.
Multiples usually run on the mothers side. So there's a bigger possibility if u were a twin or had twins in your family
Its 1 out of 80 women. It only matters a little bit more if it ran in your side. The women is the one that has to release two eggs instead of one and he has to fertallize them both. if hes a identical twin im not to sure how that works. I have faternal good luck !!