You may have heard that if your newborn has blue or light gray eyes, there's a chance they could become brown (or go green) as she gets older. But if and even when your baby will experience eye color changes is anyone's guess.

What's responsible for this magical transformation in your little one's eye color? The answer depends on the amount of melanin in the iris (the colored part of the eye) — which, in turn, is determined by the genes your baby has inherited from each parent — as well as other factors.

When does a baby's eye color change?

The most dramatic eye color changes will probably occur when your child is between the ages of 3 and 6 months old. By that point, the iris has stashed enough pigment so you'll be able to better predict what the final hue will be.

But even so, your baby's eye color may still hold some surprises. Your baby's eye color may continue going through a number of changes due to pigmentation of the iris until baby's first birthday, andyou may still notice subtle eye color changes (green eyes slowly turning hazel, say, or hazel ones deepening into brown) until she's 3 years old. Just don't expect brown eyes to revert to blue — dark eyes tend to stay dark for most babies.

Black, Indigenous and People of Color (BIPOC) infants are more likely to be born with dark, usually brown, eyes, though the shade may change slightly during the first year. Caucasian babies are more likely to be born with dark blue or slate-gray eyes that may change several times before the first birthday.

What role do genetics play in baby's eye color?

The final hue of those pretty peepers also depends on you, your partner (or your child's other biological parent) and a roll of the genetic dice.

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Since there's still a lot that's not understood about the interplay of genes and their part in determining eye color, it's hard to make hard-and-fast predictions about the shade your baby's eyes will end up. But if your child has blue or light gray eyes as a newborn, there are some probabilities:

  • If both biological parents have brown eyes, but one had a blue-eyed parent, then there's a slight chance your little one's eyes will be permanently blue.
  • If onebiological parent has blue eyes and the other brown, then your child has a 50-50 chance of having permanently blue eyes.
  • If bothbiological parents have blue eyes, then it's very likely that your child's eyes will be permanently blue.

What role does melanin play in baby's eye color?

Melanin, produced by cells, is the pigment that's responsible for giving you the color of your skin and hair (or at least the hair color you had as a child).

Just as sunlight turns the skin a darker shade, it does the same thing to eye color by way of the iris. When your child enters the world (and is exposed to bright lights of the birthing room), that light kick-starts melanin production in the iris, which can lead to eye color changes.

Just a smidgen of melanin and your baby will have blue eyes; add some more and you get green, gray or hazel; even more and a newborn's eyes will be brown or black.