I think personalities make a huge difference. However, DH was susceptible to peer pressure as a teen, but I simply wasn't. (Big surprise, I'm sure...) DH and I are both INTJs.
The difference, in my opinion, was that I was in a safe environment around people I'd known my whole life. DH is from a military family with a frequently absent father and a mother with a debilitating illness, plus a new school situation that was about as close to prison as I could imagine with new people, where he simply didn't fit in. He had no anchor.
Self-confidence--the real kind, not the "everybody gets a medal" kind--and fortitude go a long way to helping a kid fight off peer pressure. If they believe in themselves, they don't succumb so easily.
And just as an aside, when I worked for the Girl Scouts, we often quoted the stat that kids with 3 responsible and caring adults involved in their lives *besides their parents* are significantly less likely to engage in dangerous behaviors like drugs, early sexual experimentation, violence, etc. I forget exactly how much less likely, but it was a lot--like 75% less.
Reason enough to have a good teacher, piano teacher, basketball coach and/or religious instructor in your child's life!
