Buffy is a show for a mature audience. There is no way around it. I personally wouldn't let my child(if I had one)watch buffy till they were mature enough. It has nothing to do with the sex. Sex is a natural thing. Everyone on this planet is here as of a result of sex. It's what we are born to do. It's the violence that would make me balk at allowing a child to watch anything in the buffy-verse. Buffy and Angel are shows that feature a rather large amount of violence(especially Angel). Characters are constantly getting their necks broken, being dismembered, decapitated, stabbed, electrocuted, and assaulted by nightmarish creatures. Not to say that I mind those things myself.