How much do you know about genetics? It’s not always as simple as brown-haired dad plus blonde-haired mom equals brown-haired baby. The process is much more convoluted than that.
The world of genetics is fascinating. Hair color is something scientists are still learning about and is not perfectly predictable, but with a little deduction and logic, you can make a reasonably accurate guess as to what color your baby’s hair will be.
Genes determine everything about a person’s appearance. Each gene is made up of two alleles, one from the mother and one from the father. Your baby’s appearance will depend on which of those two alleles are dominant in each gene. Typically, darker colors are dominant. One brown-eyed allele plus one blue-eyed allele is likely to produce a brown-eyed child.
But this is not always the case.
All those babies that came out brown-eyed because their brown-eyed father’s allele won out over their blue-eyed mother’s allele? They have a recessive blue-eyed allele. So, when that brown-eyed baby grows up and starts another generation with a partner who has a dominant blue-eyed gene, the recessive blue-eyed allele plus the dominant blue-eyed allele has about a 50% chance of producing a blue-eyed baby. Your baby’s features are dependent on not only you and your partner’s features, but also your parents’ and your partner’s parents’, and their parents’, etc.
It’s a lot to process, I know.
Hair color works similarly. For the sake of simplicity, we’ll keep our examples based on you and your partner plus the grandparents.
If you’re a brunette, both your mother and father have brown hair, and your partner and both of their parents have brown hair, your baby is going to have brown hair.
If both of you are dark-haired, but you each have one parent with blonde hair, your baby could be blonde (approximately a 25% chance), but he or she will most likely have brown hair.
If you are blonde and your partner is brunette (or vice versa), and your brunette partner has a blonde parent, your baby has a 50% of coming out blonde.
Black hair is dominant: except in rare cases, it most always wins out. And red hair is a recessive gene, often mixing with other colors, which is how you end up with naturally strawberry-blonde or auburn hair. Being a recessive gene, a true redhead almost always requires at least one redheaded parent and the other parent to have a redheaded direct ancestor, making them a carrier of that particular recessive allele.
Scientists are still studying hair color and genetics, so this is not by any means a definitive list, but with a better understanding of genes and alleles, you should now have a good idea of what color your baby’s hair will be when he or she shows up.