I may be a teenage girl, but I can relate to some of the guys that have posted here.
When I turned thirteen, my parents gave me a book, on sex, periods and all that other stuff. A book. They left it on my bed, and asked me to read it. So I did. I'm now nearly 16, and not once has the issue of sex been brought up by either parent. Whilst I'm partially glad that they spared me the 'birds and the bees' lecture, I feel kind of let down that they didn't have the confidence to talk to me about somehting as important as sexual health. So, if I were you, I'd have that talk. Just be patient, thorough, and answer any questions they might have, because I'm pretty sure there'll be a lot of them. It may feel awkward at first, but believe me, they'll thank you for it in a few years time.
Hope all goes well,
Lauren. x