Parents: What are your views on co-ed sleepovers?

My parents only allowed it once when I was in high school and that was after my senior prom and it was only because it was a big group of us staying at a friend's house with his parents home. They never would have let me spend the night at a guy's house one on one, especially someone I was dating at the time. Once I was in college they weren't so worried about it and I spent the night at people's houses quite frequently. As a parent, I would probably take a similar stance. It would okay for a group, but not for a boyfriend/girlfriend situation.