Parenting: What is the best way for a young child to handle bullying?

I was not present for this event, but here’s how it was described to me:

My son, “E”, has long, blonde, curly hair that he’s very proud of. It’s never been cut, because he insists he loves it (evidenced by his patiently sitting through daily combing sessions like a champ). Because of this, he’s often mistaken for a girl. Most of the time, it’s no big deal. He simply says, “I’m not a girl. My name is E.” and people move on, for the most part.

My husband, Mitch, took my son, E (4 years old), to the park. There was another family there, with three kids: 5 year old girl, 6 and 8 year old boys.

At first all was well, until the little girl said something that caused E to use his go-to polite correction while the four of them were climbing on a foam animal sculpture thing.

The boys overheard it. Cue relentless teasing. “You’re a girl! You’re a girl! Girly-girl! Girly-girl!”

The sister told them “No, he’s a boy”.

My husband told the kids, “Really, you can use his name, it’s E.”

The six year old boy wouldn’t stop. “Girly-girl, you’re a gi-irl!”

My son shouts “I’m A BOY!” and shoved the kid. Hard. He fell (a whole two feet) to the ground and started crying.

The 8 year old ran to his mom to tell. “Hey, that kid pushed brother!”

SuperMom (who had been neck-deep in her iPhone until this point) storms over to my husband demanding justice.

My husband told her “Your boys were picking on my son, calling him a girl, he tried to talk his way out, and they kept picking on him. So he defended himself.”

Her: “Maybe you should cut his hair!”

Him: “Maybe you should teach your kids some respect. They want to call my son a girly-girl, but as far as I can see you have a crybaby and a tattle-tale, and they’re twice his age and size.”

Her: (Fumes and takes her kids and leaves)

Now, what do I do here? “No, E, it’s not good to push people, but I’m glad you tried to talk your way out first. I understand that you were insulted and that you’re proud of your hair and that you are a boy, but I don’t want you to think it’s an insult to be a girl – that being a girl is somehow worse than being a boy. Yes, they were mean but no, fighting isn’t the best way to solve your problems…”

Since this situation is likely going to occur considerably more often as my son ages, how should I talk to him about it? What suggestions can I give him to avoid physical confrontation? Does he have to take the bullying?

I was relentlessly teased as a youngster all through high school, and never learned the “right way” to deal with it, so any advice would be appreciated.

((This is in Social, so feel free to discuss the topics of bullying and gender discrimination openly)).