Baby Eye Color Science

It’s normal for parents to dream and imagine what their new baby may look like. One trait that often gets a great deal of pondering is the tint of the windows to the soul, eye color. While it may be impossible to determine what color your baby’s eyes will be until you can see them you can add some science to your wondering.

What gives my baby’s eyes color?

Eye color is determined by the amount of (or lack of) a pigmentation known as melanin in the iris. The human iris has two layers. A child with melanin in both layers will have brown eyes, a child with melanin in only the back layer will have blue eyes and a child with a little melanin in both layers will have green eyes. The varying shades of blue, green, and brown are produced by the degree of pigmentation in each scenario. For example if someone had a great deal of melanin in both layers their eyes may appear a deep almost black brown, a person with no melanin in the front layer and very little in the back layer would have very light blue eyes. Albino eyes (pink) are a result of no pigmentation causing the eye to take on the color of the blood vessels in the back of the eye.

What determines what color my baby’s eyes will be?

You and your partner’s genetics which then form your baby’s genetics tell his or her body how much melanin to deposit and where. You can get a rough idea of your baby’s possible eye colors from looking at you, your partners, and both of your parent’s eye colors. For example if all 6 people have blue eyes it highly probable the baby will have blue eyes. If no one in the group has blue eyes it’s nearly impossible for your baby to come out with blue eyes. Keep in mind that green and blue are both recessive gene traits meaning having even 1 person in the equation with brown eyes significantly increases the chances of your baby having brown eyes as well while having one person with blue eyes offers a chance but still a very, very small one.

This is why America’s blue eyes are turning brown. In 2000 about 50% of American babies had blue eyes, by 2006 that number had dropped to about 16%. This change is a result of the increase in recent years of cross-ethnicity marriage. Blue and green eyes are most common in individuals of Caucasian decent and as the melting pot mixes races where the dominant gene dark eyes are more common are taking over.

Why will I be surprised by my baby’s eye color overtime?

Your baby’s eyes actually will not stay the color they’ll appear as you gaze into them just after labor and delivery. When babies are born the melanin that provides their eyes with color has not entirely synthesized. Most Caucasian babies are born with a dark slate color eyes and most non-Caucasian babies are born with dark brown eyes. In time as melanin develops your baby’s eye color will change. Though a baby born with brown eyes will not develop into a blue or green eyed baby he or she may end up hazel or amber. A baby born with slate eyes may be blue or green in time. Your baby’s eye color will likely be close to the color they will remain for life sometime between 6 months and 1 year of age. However some babies, especially those of Caucasian decent can still experience eye color changes up until age 5. Some adults even notice small changes in their eyes over time.


What determines eye color?

America’s Blue eyes turning brown

How late can my baby’s eyes change color?