Responses
It's actually the opposite; twins are more likely to happen on the mother's side rather than the father's. Fraternal twins happen when the ovaries release multiple eggs. Granted, a father can pass down this gene to his daughter, but it doesn't increase the possibility of his child's mother having twins. Identical twins on the other hand are spontaneous as the single egg randomly splits into two.
Them having twins wouldn't be the most shocking thing the world. I hear twins are more likely on the parental side especially if there's a history of having twins in the family. Rather, than on mother's side (￣ε(#￣)Σ