Sex under your roof..

How would you feel about your 16 or 17 year old daughter OR son having sex in your house while still living with you ? Just wanted to get a few people perspective on this whole thing. I happen to have lived with a family member who's daughter used wakes me up almost every weekend at night with random guys because the noises were audible enough through the wall between her room and I . Her mother knows and just simply states "she is out of control" .. I'm just like "OK then" & move on lol