Where did you hear this? There are lots of girls who are attracted to guys who aren't total jerks--a sense of adventure just excites them. It's not like nice guys are 100% unattractive to girls. Hell, I consider myself a nice guy.
This didn't happen recently, but some old music is reminding me of it, and I figured I'd put this out there as a reason to not have sex (which doesn't make sense if you've seen what side of the debate I'm on).
I've said a number of times how sex is very bonding with your partner. It's an act of love, and it makes you feel closer than ever with your boy/girlfriend, so long as it's the right person. (I would assume--I've only had sex with one person and she is right for me.) However, if two teenagers were to have sex (and this is probably true for adults, too), and then break up or leave each other or whatever, the emotional stress is that much worse, and it'll likely be traumatizing (similar in the way that KartWheelyGirl was 'traumatized', for lack of a better word--something so devastating happens and you, as a teenager, cannot correctly cope with it).
So that's one reason to not have sex.
well man i dunno if you live in an envoironment where things are different than the one that i do but the fact is that you fail to get a girl in london if you are not good looking and a poser. And the fact that girls do not like nice guys was mentioned on the Relationships thread and someone even gave a link to a website exclusively made to explain why nice guys fail.
I also want to share the experiece of a friend of mine... She dated and had sex with a guy for 2 years and that guy (from what ive heard good looking and athletic) always treated her like garbage and she would always forgive him and what not. Eventualy she was pregnant and he left her and the boy saying all the bullshit assholes do when they are not ready for responsabilities. She had the boy and kept saying that she was stupid by liking him and told me and my cousin (shes one of my cousin's closest friends) that she will be a single mother and will never want to the the boy's father ever in her life. Another fact is that her parents never liked him(my friend's ex) since day 1 and always told her that he sucks.
Basically, 1 year and a half she had the baby i hear the news from my cousin.
SHE WENT BACK TO HIM...