Actually in Greece there is no peer pressure in any subject. There are barely any teens who will encourage you to have sex or smoke. But it certainly isn't due to their own insticts. Teens are not emotonially mature enough to have sex due to their own insticts. It's mostly the celebrities who talk openely about sex in my country and influence young people to have sex.
Teens today have sex mostly because of peer pressure, rather then their own instincts. Society today places and emphasis on sex, through media, movies and music. Everywhere teen go, they see that sex is a good thing. In schools, it is viewed as a bad thing if you have not had sex while your peers have.
Nowadays, sex has lost all of its meaning as to what it means years earlier. Sex used to be an intimate, and special way to show how we felt towards another person. Now its just become a race. I'm not exactly at an age where I should be thinking about having sex and I don't have peer pressure on me but areas (towns) around me do, a lot. Teens now just have sex in order to "bump up" their social status or to fit in which shouldn't be happening at all.
I am a teenager and I am quite aware of why they do it. Because they like it. Period. Peer pressure? There is no peer pressure. If a girl wants to have sex the guy will say "Hell yeah!" from hormones and instinct. There may be some cases where peer pressure is a factor, but you will almost never find a teen who isn't willing to have sex.