Seeing that I don't see marriage as something that I would necessarily want my kids to aspire to unless they want it (I do want them to have a long term loving partner of whatever gender they prefer but don't think marriage is the be all and end all) so I can't really talk about sex before marriage. I have no religious or cultural basis to make any expectations of them and I think that it is my responsibility to teach them to think for themselves and have the self-belief that they will do what is right for them and do it for the right reasons.

Just as an aside - if your child came out as being gay and hence they are unable to get married (as the law currently stands), how would you approach sex with them from that perspective and would it make a difference if you had a son or daughter making this decision?