When will my baby's eyes change colour, if at all?

As you stare lovingly at your newborn, you are captivated by the sea of rich colours reflecting back at you in their beautiful eyes. Maybe they are a shade of light blue or grey or a deep brown. Whatever the colours are sparkling back at you, you wonder—will my baby’s eyes stay this colour, or will they change colour over time?

This is a thought that goes through many new parents’ minds. Predicting a baby’s eye colour is not as easy as it seems, but having said that, we’d love to shed some light on this to give you a better understanding of your little one’s eye colour.

First of all, let’s take a look at how your baby’s eyes get their colour.

How do eyes get their colour?

Ultimately, the colour of your baby’s eyes depends on both your and your partner’s genetics and how each of your genes mix together.

Dark-skinned adults will usually have dark-coloured eyes. Adults who have lighter-coloured eyes are more likely to have lighter skin. While there is not enough research on eye colour in infants, the same pattern does seem to be true for babies.

There have been many studies to show how most Caucasian babies are born with slate-grey or dark blue eyes, while a baby of another race (Black, African, Asian, Indian, Native Hawaiian, or other Pacific Islander) will usually be born with dark brown eyes. But the colour of a baby’s eyes can change once their eyes are exposed to light outside of the womb. This is because the iris (the coloured ring that surrounds the pupil) has colour-producing cells.

This colour-changing process usually takes six months; however, a child’s eye colour can change up until they are six years old. Caucasian children can even experience changes in their eye colour well into adulthood.

What role does melanin play in your baby’s eye colour?

Melanin is the pigment responsible for giving babies the colour of their skin, hair, and eyes. The colour of the iris is determined by melanocytes, which are the cells that produce melanin. Melanocytes respond to light by increasing melanin production, usually over the first year of your baby’s life. Depending on how much melanin is produced, it’s likely that your baby’s eye colour will begin to change slightly after birth. Minimal melanin means your baby has blue eyes; slightly more melanin means their eyes will be green or hazel. And if your baby has brown eyes, this means the melanocytes are producing a lot of melanin.

What role does genetics play in your baby’s eye colour?

Did you know that there are as many as 16 different genes involved in determining what eye colour your baby will have? The two most prominent of these are the OCA2 and HERC2 alleles, which are responsible for the greatest proportion of eye colour variation.

For many years, brown eye colour was considered the strongest or most dominant trait, and blue the more recessive; however, today, determining eye colour is actually not that simple. This is because eye colour is not influenced by only one or two genes; your baby’s eye colour will be determined by all 16 genes that they inherit from you and your partner. This is why parents with brown eyes can sometimes produce a baby with blue eyes, although this is rare.

But that being said, is it still possible to predict your baby’s eye colour?

There is a lot more we still need to understand when it comes to the interaction between genes and their role in determining what eye colour your baby will have, so it’s hard to accurately predict what eye colour your baby will have. Having said that, there are a few probabilities that are interesting to note:

Two brown-eyed parents: it’s likely that your baby will have brown eyes, but if either you or your partner have family members with blue, green, or lighter-shade eyes, there is a chance that your baby could have an eye colour other than brown.
Two blue-eyed parents: there is a high probability that your baby will have blue eyes, although this isn't 100% guaranteed.
One blue-eyed parent, one brown-eyed parent: there is about a 50/50 chance that your baby will have blue eyes.
One or both parents with green or hazel eyes: your baby could have either green or hazel eyes, but again, this is not guaranteed.

As a general rule, a baby’s eyes get darker over time rather than lighter. So if your child is born with blue eyes, they could turn green, hazel, or brown. But if your baby is born with brown eyes, then it’s very unlikely that your child’s eyes will turn blue.

It is nearly impossible to predict the colour of your baby’s eyes by looking at your and your partner’s eyes alone. Predicting eye colour is a lot more complicated than that. But hopefully, this ambiguity provides some nice surprises along the way, and you and your partner can have some fun guessing!

Will my baby's eyes change colour?

On Unii’s Baby Development Journey, we look at when your baby’s eyes change colour.