In preschool.

I'll probably get flamed, but you need to tell your son to not let anyone get away with hitting him. Best way, IMO, is to hit back-hard. The wanna-be-bully will find an easier mark. Teach him now, it's not going to get any easier. He can't go running for help every time.

My mother told me to never, ever fight. If someone wanted to hit me, that was "their problem". Uhh, no-it was my problem-I was the one taking a beating. It never stopped until I decided that my mother didn't know what she was talking about and I couldn't take it anymore. I was a strapping farm boy, the first time I picked up 1 of the wannabe bulles by his neck and lifted him up off the floor against the wall with one hand the bullying stopped. Then they suddenly wanted to be my friend.

Edit-Later, when I was 25 or so, I heard another guy my age remark that his Dad had always told him, "I don't ever want to hear that you started a fight, but if someone starts one with you, don't back down."