Doting dads often aim for a son they can throw a baseball with in the backyard, and moms yearn for a little girl to doll up in pink dresses and ribbons. Sounds like a stereotype, right? But a new survey of more than 2,000 people in Canada found that moms and dads do have a preference when it comes to the sex of their child.

The results surprised authors of the study, which was published in the journal Open Anthropology. They thought the subjects would show little or no preference, but no matter how they framed the questions, there was still a strong leaning toward one gender or the other. But why? Scientists think it could have something to do with our ancestors.

Men simply have a greater ability to father more children than women could ever birth. But women’s penchant for daughters is not as clear. It could be a desire to share the experience of motherhood, or a need to foster mother-daughter emotional bonds. They could even want their girls to enjoy the same social and financial empowerment of modern-day womanhood.

But behind the notion that dads want boys and moms want girls, there’s concern that learning baby’s gender before he or she born could lead to abortion in parts of the world where males are valued more than females. Research revealed a new blood test that can determine a baby’s sex as early as seven weeks.

Long before science sought an answer to that question, parents have been trying all kinds of tricks to sway nature in one direction or the other.

Supposedly, conceiving closer to ovulation will bring you a boy, and including nuts and dairy in your diet will get you a girl.

But if you just want to have a healthy baby, it’s best to follow solid prenatal nutrition rules, like avoiding caffeine and alcohol and eating foods rich in folate, iron and calcium. Your baby is more likely to a healthy blessing, boy or girl.