Yeah, force-keeper, but there's more to prenatal care than finding out the sex of your baby. You still go in for doctor's exams, etc. even if you don't want to know. And in the course of these exams a twin would eventually have been discovered. And that's something a medical expert *would* pass on, regardless. You never hear prospective parents say, "And don't tell us if we're having a multibirth--we want it to be a surprise!" You know? And please, I'm not trying to get all critical on ROTS. The truth is, I loved this movie. It's just somthing I wondered about while watching it.