When I was my son’s age, I found a Barbie in my grandmother’s basement. It was the only toy in the house, left over from when my mother was a girl. I was four years old, too young to know that boys aren’t supposed to play with dolls. For a few short moments, I put Barbie in her dream house and played at being a mother.

The game ended when my brothers found me. I’d been caught with a girl’s toy. The ridicule I received was so harsh that I still remember it today. Barbies, I was told, were “for girls.” I would never touch a doll again.

I realized how much that moment still affects me when my wife suggested getting our son a Doc McStuffins toy.

“We can’t,” I told her, an echo of my brothers’ torment flashing in the back of my mind, “It’s for girls.” The pink packaging that held the doll sparked revulsion inside of me. My son had been acting aggressively, and my wife was worried that all my son’s heroes were violent action stars, who play at killing. She wanted to offer him a more positive role model.

I couldn’t explain why playing with a girl’s toy was bad for a boy. It was just something I accepted, something so deeply ingrained in me that I didn’t question it: Boys play with superheroes and girls play with dolls. If that order was broken, I felt something might go terribly wrong.

The evidence, as it turns out, shows the exact opposite to be true. When children are given gendered role models, according to two recent studies by BYU’s Prof. Sarah Coyne, it actually creates major behavioral problems. When they play with each other’s toys, on the other hand, they grow up to be more empathetic.

It’s not what I’d expected, but giving my son a doll just might be the best thing I can do for him.

Superheroes make boys more aggressive

When a boy watches a superhero punch his way through all of life’s problems, some parents give it a pass because they hope their child will notice the good the hero is doing. Superman, after all, isn’t just fighting Lex Luther; he’s saving Lois Lane. He’s brave and compassionate, and we hope our kids will imitate that heroism.

As it turns out, kids don’t pick up on those positive things at all. According to Sarah Coyne’s study, superheroes have the exact opposite effect. They make boys less compassionate. Coyne found that after a year of heavy exposure to superhero programs, boys pick up their heroes’ violent habits. All that fighting on TV affects them, and they become notably more aggressive and physically violent with their classmates.

Unfortunately, the superheroes’ good behavior doesn’t rub off the same way. Instead of becoming superheroes themselves, these kids are actually less likely to help classmates who get bullied.

There’s a reason for this. At a young age, kids don’t tend to pick up on why superheroes are fighting. They just focus on the excitement of the violence. Instead of teaching them to protect each other, kids become desensitized to abuse. When they see a kid getting picked on, they barely even notice it and don’t do anything to help.

Kids who don’t regularly see this behavior, on the other hand, are shocked by it, so they’ll actually be more likely to do something about it.

Princesses make girls feel more helpless

The exact opposite happens with girls and princesses. Coyne conducted another study on how Disney Princesses affect little girls’ behavior and self-esteem, and the results were devastating. She found that, after a year of being heavily involved with princesses, girls become more stereotypically “feminine,” according to society’s expectations of the term.

These girls show less confidence in math and science, more fear of trying new things or of getting dirty, and have lower self-esteem about their bodies. When they play with princesses, girls are exposed to an ideal concept of what they think they’re supposed to be. They’re taught, even if indirectly, that they’re supposed to be thin and pretty – and this can start influencing thought patterns in kids as young as age three.

Playing with dolls makes boys better

The thing is, princesses have the exact opposite effect on boys. Coyne did her tests on both genders and found that, when a boy plays with princess dolls, he actually grows to be more helpful and his body image improves.

It’s a little unexpected, but it sort of makes sense. A boy who watches princesses sees the opposite of aggressive, muscle-bound supermen. Instead of absorbing an ideal of what he’s supposed to be, he’s learning what it’s like to be somebody else. He’s becoming more sympathetic to others and more confident in his own interactions.

It doesn’t exactly go both ways. Superheroes seem to have a bad effect on both genders. Girls can benefit, though, from a role model who gets dirty and solves problems. When they see that they can be resilient and resourceful, they learn to tackle tough issues themselves instead of passively waiting for someone else to save them.

Which means that my wife was right. Doc McStuffins, with her love of STEM, really is the perfect role model for a little boy.