I only tell my daughter what I think she "needs" to know, and she is comfortable enough to come talk to me because we talk about alot of things. You have to be honest but there isn't a need to go into a full blown detailed discussion. I also bought my daughter a book that talks about growing up and develping and then asked her if she had any questions.

Since you have a son I would instruct his father to tell him the truth about respecting women and himself and just because other boys or guys are talking about it doesn't necessarily mean that is the true what they are telling him and he needs to talk to his father and get advice from him and that the both of you want him to be responsible and to think things through. What will you gain? What will you lose? What will you regret? What will you be glad you achieved? What can you do to become a responsible young man? What are some ways to show respect to women? What are the ways you can respect yourself?

I guess there are just a few questions to ask him and then discuss the answers. Let him know it is definitely okay to come and talk to you guys about anything no matter how bad he thinks it may be or embarrassing.