you CAN get a female pregnant after she is already pregnant. Superfetation is what it is called. I worked at a fertility clinic and this DOES HAPPEN but very rare.
In order to have a double pregnancy, you’d have to either ovulate while pregnant or have two uteri. Both of those scenarios, again, are highly unlikely.
Ovulating during pregnancy happens so infrequently doctors haven’t been able to study why it may occur.
While uterine abnormalities aren’t quite as uncommon, doctors typically see people with a divided or partially formed uterus, not two separate uteri.
This condition, called didelphic uterus, is rare. While it can cause a double pregnancy, it’s more likely to result in a miscarriage than two pregnancies at the same time.