Years ago, I went to a wedding at an estate in South Carolina—hanging moss on giant oaks, rolling lawns, and a pond that looked like it belonged in a painting. Absolutely breathtaking.

I was there with a group of friends, including the wife of one I’ll call Dina. Dina wasn’t exactly known for her warmth. By the time the reception dinner rolled around, I found myself seated next to her. She was swatting at the air, arms flailing, slapping her legs and face in a full panic. That’s when I saw it: the wall behind us was covered in mosquitoes. And here’s the thing—those little bloodsuckers were only after her. Not me. Just Dina.

Here’s the science: some people naturally attract mosquitoes. Your DNA and genetic markers determine whether you smell delicious to them or not.  Genetics don’t just influence mosquito-magnet status—they also play a role in eye color, freckles, hair loss, even whether you can roll your tongue (which I can). Science also shows that genetics affect things like being a night owl or a morning person, whether cilantro tastes like soap, or if you have ACHOO syndrome (sneezing in bright light).

And it turns out traits like optimism, persistence, and confidence are also partly genetic, with estimates suggesting that 25% to 50% are hereditary. This is due to the OXTR gene, which is linked to the oxytocin receptor and impacts stress and social interaction. Some people are naturally wired to see the glass half full, to persist, to feel confident. Sometimes, it really is because they were born with the right DNA.

According to The Confidence Code by Katty Kay and Claire Shipman, our brains have something called plasticity. That means we can physically rewire our brains through repeated thought patterns. We can create new mental habits. Optimism can be learned. Persistence can be practiced. Confidence can be built.

If you didn’t get the genetic lottery ticket for positivity and self-assuredness, you can still train your brain: challenge negative thoughts, build positive experiences, and surround yourself with people who lift you higher.

Dina may have been genetically predisposed to attract mosquitoes. The rest of us? We get to choose the kind of energy we own and project.