Since the day you found out you were expecting, you’ve probably been dreaming about what your baby might look like. Will they have your eyes? Your partner’s curls?
Only time will tell. With hair color, the science isn’t very straightforward.
Here’s some information about the basic genetics and other factors that determine if your baby will be blonde, brunette, redhead, or some shade in between.
When Hair Color Is Determined
Here’s a quick pop quiz. True or false: Your baby’s hair color is set from conception.
When the sperm meets the egg and develops into a zygote, it typically gains 46 chromosomes. That’s 23 from both the mother and father. All of your baby’s genetic traits — hair color, eye color, sex, etc. — are already locked in at this early stage.
What’s even more interesting is that each set of chromosomes that parents pass to their children is entirely unique. Some children may look more like their mothers, while others look more like their fathers. Others will look like a mix, from getting a different combination of chromosomes.
How exactly do genes interact to create hair color? Each of your baby’s genes are made up of alleles. You might remember the terms “dominant” and “recessive” from grade school science class. Dominant alleles are associated with dark hair, while recessive alleles are linked to fair shades.
When the genes meet, the resulting expression is your baby’s unique phenotype, or physical trait. People used to think that if one parent had blonde hair and the other had brown hair, for example, the recessive (blonde) would lose out and the dominant (brown) would win.
The science makes sense, but according to the Tech Museum of Innovation, most of what we know about hair color is still in the theory stage.
It turns out, there are many different shades of brown. Brown-ebony is nearly black. Brown-almond is somewhere in the middle. Brown-vanilla is basically blonde. Most of what you’ll read about genetics presents hair color as either dominant or recessive. But it’s just not that simple.
Since multiple alleles are at play, there’s a full spectrum of hair color possibilities.
How much and what type of pigment is in a person’s hair and how it’s distributed helps make up the general shade.
Even more interesting is that the amount of pigment in a person’s hair, its density, and its distribution can change and evolve over time.
There are two pigments found in human hair:
- Eumelanin is responsible for brown/black tones.
- Pheomelanin is responsible for red tones.
Baby Hair vs. Adult Hair
If you’ve flipped through old baby pictures of yourself, you may have noticed that you had lighter or darker hair as a baby. It may have changed in your toddler and preschool years, too. This situation goes back to the pigmentation in the hair.
A study published in Forensic Science Communications recorded the hair color of 232 white, middle-European children in Prague. They uncovered that many of the children, both boys and girls, had darker hair in the first half year of life. From 9 months through age 2 1/2, the color trend lightened. After age 3, hair color became progressively darker until age 5.
This just means that your baby’s hair may change shades a few times after birth before settling on a more permanent color.
Babies born with albinism may have little or no pigmentation in their hair, skin, and eyes. This disorder is caused by a gene mutation. There are several different types of albinism that affect people in different ways. Many are born with white or light hair, but a range of colors is also possible.
This condition can cause vision problems and sun sensitivity. Though some children are born with very light blonde hair, children with albinism will typically have white eyelashes and eyebrows.
Albinism is an inherited condition that happens when both parents pass along the mutation. If you are concerned about this condition, you may want to speak with your doctor or a genetic counselor. You can share your family’s medical history and ask any other questions you have about the disorder.
So, what color hair will your baby have? The answer to this question isn’t so simple. Like all physical traits, your baby’s hair color is already determined and coded in their DNA. But it will take some time to fully develop into the exact shade it will be.