I attended an elite university. My first year there, I met a classmate whose roommate had arrived at the university without the slightest knowledge of sex. She became extremely upset when she discovered that boys would be living in her dorm. She had convinced herself that women got pregnant by sleeping in the same building as men, that men somehow emitted "spores" in their sleep that could impregnate sleeping women. She'd grown up as the daughter of a widow and had no brothers, so in her own home, she'd never tested this hypothesis.
The classmate I met alerted a freshman counselor to the situation, and the counselor arranged for the girl to see a psychologist at Student Health so that the birds and bees could be properly explained to her. I gathered that she was pretty shocked by the information, and I really had to wonder how she had been bright enough to get into that university without ever having learned anything at all about sex.