Sex was always discussed freely in my home growing up. Not with my father (my parents got divorced when I was young), but neither of my parents took any pains to hide sex from me. They both took me to movies when I was young without considering the sexual content...they both had good taste in movies, though, so the advantages of becoming a film buff far outweigh any consequences to sexual material at a young age. In my opinion, at least.
I don't really talk about my own sexual experiences with my family, per se, but we do discuss sex without timidity or embarrassment. My mother knows that I am kinky (through an unfortunate circumstance that I won't get into here - it's too much of a bummer, lol) but she's not one to freak out about such knowledge.
So I've never thought about the subject of sex as 'taboo,' but I talk about it on a personal level with very few people. Excepting of course the 10,000 or so people who visit the TFP.