Chitty Chitty Death Bang - S1-E3
Question: In the flashback where Lois gives birth to Stewie. The doctor says they aren't done, and she says "Oh my God, is it twins?" With this episode being made in the late 90s, would it even be possible for a twin to go undetected until birth?
Answer: Parents can request to not know the results of an ultrasound if they want to be surprised about the baby's gender. The doctor still would have let them know whether or not to expect twins, though, so the doctor is just as puzzled as Lois to find something else in there.
Captain Defenestrator