Why are some babies born with gray eyes?

When your baby was born, you may have noticed that he had gray eyes, perhaps a little bluish; it was not your imagination, many little ones have a light color, and over time it darkens. The reason is that the cells that produce melanin in your body are immature, and the iris color is not yet defined by genetics. However, this curious change does not occur in all babies, although expected. Some are born with brown eyes, and their color is already defined; others become darker, and some more have blue, green, or brown eyes from a very young age. Why are some babies born with gray eyes?

Melanin is responsible for defining the color of the eyes.

In an article for the American Academy of Pediatrics, Dr. David Hill explains that the reason why the color of the eyes changes is due to melanin, the protein responsible for giving pigment to our skin, hair, and eyes.

“When the baby is born, the eyes may look gray or blue because the melanocytes (the cells that produce and secrete melanin) respond to light and have spent all their time in the dark up until then”, says Hill.

Over time, as the baby grows and the cells mature, the color of the eyes can change from grayish blue to dark brown.

At what age is eye color defined in a baby?

The work of the melanocytes varies and can be defined from six months to one year; only then is it possible to know the actual color of the baby’s eyes.

“It is tough to know a specific date in which the color of the baby’s eyes is defined; it is a process that goes according to the production of melanin in the organism, that is, the action or inaction of the melanin determines to what extent it is going to be pigmented”, indicates Gloria Britez, a pediatric ophthalmologist.

If the melanocytes secrete little melanin, the baby will have blue eyes. If they secrete a little more, they will look green or yellowish. When these cells work hard, they will look brown, the most common eye color. They can even turn very close to black, which is very rare.

In case of children who have already defined light-colored eyes may have slight variations up to the age of three since the iris “stores” melanin until that age.

You can read: Should I bathe my baby daily?

How genetics influence eye color

Genetics has a lot to do with it. The iris, which is the colored part of the eye, is a 100% hereditary trait that, as we mentioned, depends on the amount of melanin found in this area of the eye and how it is distributed. This information is explicitly transmitted through chromosomes 15 and 19.

This color will likely be passed on to the children if the parents are light-eyed, although it does not happen every time. There are many combinations.

Suppose one of the grandparents has light-colored eyes, the probability that the baby is born with blue or green eyes increases. If one of the parents has light-colored eyes and the other brown, there is an equal chance that the baby has eyes of one or a different color.

“There are also cases where both parents have brown eyes, but the children are born with blue eyes. That’s how genetics is, unpredictable. It might be that some uncle or grandparent has green eyes, and the children inherit that color. Other times one eye is of one color, and the other has another pigmentation, or it is by sectors. In that case, we, doctors, are obliged to investigate a little more because it can be a problem. There are also moles in the iris that we have to observe and control”, adds Britez.

Your baby’s eye color is as unique as he is. Whatever the shade, you will not be able to stop loving that sweet look.

Translated by: Ligia M. Oliver Manrique de Lara

Spanish version: Here

It may interest you: How can you prevent colds in children?