My mother recently told me a story about my four-year-old daughter. After asking her to count the Barbies they were playing with, my daughter told my mother to do it herself because she wasn’t good at counting. She continued telling her grandmother that her brother was “good with numbers,” but not her. When my mother relayed this story to me, I felt a pang of failure.

With a son and daughter at basically the same maturity level, my home is a working lab on childhood developmental and gender psychology. Every day I’m encountered with the differences between my boy and girl – how they play, develop, learn, and perceive the world around them.

I encourage education. My children and I read, play, and do activity sheets every day. My daughter is exposed to both sets of gender specific toys, as well as gender-neutral toys, like LEGO, puzzles, board games, and tool sets. She has more aptitude and ability with LEGO than my six-year-old son. Despite the fact that he’s not allowed to touch her, having an older brother means that she silently absorbs more daily hits than a professional hockey player. And, she’s outnumbered in her preschool by boys at a ratio of three-to-one. The point is – she’s not cuddled and is well able to stand up for herself.

How could she have been exposed to this classic gender misconception at her young age? That as a girl, she’s not (or can’t be) good at math? Could she be repeating something that she’d heard?

I certainly hadn’t said anything of the sort. Not me, with an engineering degree from an Ivy League University. I didn’t excel through all those semesters of calculus, chemistry, and quantum physics for her to write herself off that fast. I would never have slapped a prehistoric gender label on them, calling my son good with numbers, while my daughter is better with words.

Could she have heard that at school or on television? I hope not. I’m pretty sure teaching girls that they’re not good at numbers is not part of her preschool curriculum or Nick Jr.’s programming message.

I think that my daughter was being nice to my son, whom she mothers to death, like me, despite being two years his junior. To be honest, he isn’t as verbal as she is. Maybe she already knows that reality. I think that she was trying to give him his thing, and I praise him over his math worksheets, so she’s following suit. But just because he counts his collections of toys like Rain Manand she can recite Disney movies verbatim, I’m not going to let her think that she can’t be good at math too.

It’s a reality that young girls need extra encouragement in pursuing interests in math and science. So many societal messages focus on the princess culture. We tell our daughters that they’re pretty, we give them dolls, and we let them watch movies that teach them that their prince will rescue them.

When I was applying for college, I was torn about what major to select. I had a teacher who sat me down and told me those labels about being a math-person and not–a-math-person were just lazy ways of limiting yourself. It was a great honest conversation and I felt like an adult having it with him. “You have to be good at everything to be successful,” he told me. “Don’t think that you are one or the other. Really, you have to be both.” More confused than ever, I chose to study engineering because I was good at math and science. But now, I realize his point was that I was too young to rule anything out. He encouraged me to be good at all subjects, including writing, another one of my passions. And thankfully he did, as I became a technology lawyer and now a writer, so I did (do) need all those skills.

That’s what I have to teach my daughter; it’s up to me to combat this math gender stereotype. I tell her every day that she’s a great counter. We practice numbers before I let her play “princesses and palace pets go to dance class.” I need to praise her imagination (she doesn’t need much reinforcement there), but also her kindness, her work ethic, her ability to solve problems and puzzles, her sense of humor, and how she’s a great builder.

If we encourage girls in the same way we encourage boys, we give them the lifelong gift of options. We want our daughters to have the luxury of deciding their own career paths. We don’t want to pigeon hole them into only studying the traditional female subjects in the liberal or fine arts. Because women need to know math too. As a stay-at-home mom or the President of the United States, she has to be able to manage her monthly expenses or the national debt.

I guess teaching her to have options starts at age four.