On Welcome Back Kotter ,in the episode where his wife is giving birth to his twin daughters, first the doctor comes out and says he has "A bouncing baby boy." Kotter doesn't hear him, so the doctor repeats, "A bouncing-" but gets interrupted by the nurse and he has to go back to the delivery room. When he comes back he says he is the father of twin girls... Now, that doctor pulled the first girl out. How could he mistake it for a boy? There's an obvious difference between the legs!