Yea, I don't believe that the doctors can see multiple babies' genders in the belly. Cause I know even with the pregnancy controller mod I have. Where it shows you how far along the mom is, how many hours til the mom goes into labor, if the mom is showing or not, and what the gender of the baby is(and what you can change it to), it only ever tells what the gender of the first baby is if there are multiples or not. I guess there is some kind of code that makes that true for the doctors as well. So unless you get a mod where you can tell genders of more than one baby, I don't believe the docs can do so on their own.