Twin Phobia

Johndora
Ok ladies I have a question about twins. My husband is an identical twin. His twins has one child, a boy. His sister has 3 boys. My husband doesn't have any yet but we want one. I already have four children. 3 boys and 1 girl, whats the odds of us conceiving twins? They run in his family pretty strong. My maternal grandmother got pregnant with twins, but my mom didn't and none of her 3 kids. Is it true that the more children a woman has the more chances she has of conceiving twins? I want to avoid this situation lol. Is there a way? (Dumb question) answers please!!!! Go!!!!!