I am an atheist. I have no problem with pre-marital sex. In fact, I wish I had more of it!
I was raised in a Hindu household, where sex was not even discussed. Part of the reason I began to question the beliefs that my parents instilled in me was the lack of openness to contemporary issues, especially taboo issues like sex, alcohol, etc.
I think too many religions have turned sex into a "dirty" act which needs to be hidden. It's so hypocritical, since biologically we are so driven by our desire for sex.
Perhaps that's why so many "religious" types end up committing sex crimes, etc.... it's their suppressive religious background which drives them to do things which they were never "supposed" to do. Anyone else agree? I guess that should be the topic of another forum altogether, eh?