The author is seriously confused.
1) Parents are extremely influential on their children,
2) Their children are going to have sex regardless of what their parents think so the parents should just go along with it....
I propose option 'three'....use parental influence to help their kids make good safe decisions regarding sex, with abstinence always being the best one.
But that might result in the kids not thinking that I'm "So Cool", and they might not be my best friend anymore, troubling as that is to me. /s
Sex sleepovers are just wrong. The home should be somewhere where kids can still be kids. JMHO