Why?

Today all of CLS-FT students were invited to attend the talk about Sexual Transmitted Disease..Well, actually there is nothing special about that. Gonorrhoae, Clamydia, AIDS and a lot of others STD were mentioned in every similiar talk like today's. I was just wondering why there is still an increase of the figure of the STD people, especially AIDS. In fact, we have known that STD is incureable illness, and practice of free sex should be avoided and so on... However, ironically it seems to become a common thing for teenagers... And the same scenario always rotate, then teenagers regret of what they have done after they know they will meet their doom soon. Is free sex considered as a prove an open-minded, modern person? Or maybe peer pressure, or just an excuse? I don't know.. Life itself is tough enough.. Why should we put an extra pressure on our life? Human beings are indeed getting crazy and crazier.