Eye Color Genetics - All About Vision (2024)

HomeEye CareEye Anatomy | Eye color genetics

By John Egan

Eye Color Genetics - All About Vision (1)

Genetics’ complicated role in eye color

Whether your child is born with brown eyes or blue eyes — or any hue in between — involves a complicated game of genetic roulette. But human eye color genetics aren’t as simple as looking at the parents’ eyes and then predicting a child’s eye color.

At one time, researchers thought that only one gene passed eye color from parents to their children. This led to the belief that a child whose parents shared an eye color (such as brown) couldn’t inherit a different eye color (such as blue).

It turns out that isn’t quite accurate. Scientists now know that a collection of up to 16 genes plays a role in eye color genetics. So, it’s entirely possible for parents with brown eyes to welcome a child who’s eyes are a different color into the world. Although those scenarios are uncommon, they do happen.

Ultimately, the parents’ eye colors can help predict their child’s eye color, but it’s only one factor.

Baby on the way?
While it's fun to play the guessing game, it's virtually impossible to accurately predict the color of your newborn's eyes. The genetics that determine eye color are simply more complex than, "well I have blue eyes, my partner has brown, so Baby's eyes will be..."

There are, however, other genetic predispositions that are important to watch out for, like glaucoma and macular degeneration.

So keep on guessing Baby's eye color. Then schedule an eye exam for you and your partner to discuss eye problems that may run in your family and get your own precious eyes checked out!

What color eyes will my child have?

There’s no guarantee when it comes to your offspring’s eye color. While a baby inherits half of their eye color genetics from one parent and half from the other parent, the way that the multiple genes interact also plays a role in determining eye color.

Differences in eye color are also influenced by differing amounts of melanin, the pigment responsible for eye color (plus hair color and skin tone).

For instance, many white non-Hispanic babies are born with blue eyes because they don’t have the full amount of melanin present in their irises at birth. As the child grows older, if they’ve developed slightly more melanin in their irises, they may end up with green or hazel eyes. When the iris stores a lot of melanin, the eyes will be amber (a golden brown), light brown or dark brown.

Even though you don’t know the amount of melanin your baby will have, you can still get a pretty good sense of eye color from the parents’ eye colors. As the American Academy of Pediatrics explains:

  • Two blue-eyed parents are likely to have a blue-eyed child, but it’s not guaranteed.

  • Two brown-eyed parents are likely to have a brown-eyed child. Again, it’s not guaranteed.

  • Two green-eyed parents are likely to have a green-eyed child, although there are exceptions.

  • Two hazel-eyed parents are likely to have a hazel-eyed child, although a different eye color could emerge.

  • If one of the grandparents has blue eyes, the odds of having a baby with blue eyes increases slightly.

  • If one parent has brown eyes and the other has blue eyes, the chances of having a brown-eyed or blue-eyed baby are roughly even.

The Fertility Institutes, which offers fertility services in California, New York, Utah and Mexico, offers the following odds of a baby’s eye color based on the parents’ eye colors. (Due to rounding, percentages don’t always add up to 100%.)

  • Both parents with brown eyes: 75% chance of baby with brown eyes, 18.8% chance of baby with green eyes, 6.3% chance of baby with blue eyes.

  • Both parents with blue eyes: 99% chance of baby with blue eyes, 1% chance of baby with green eyes, 0% chance of baby with brown eyes.

  • Both parents with green eyes: 75% chance of baby with green eyes, 25% of baby with blue eyes, 0% chance of baby with brown eyes.

  • One parent with brown eyes and one parent with blue eyes: 50% chance of baby with brown eyes, 50% chance of baby with blue eyes, 0% chance of baby with green eyes.

  • One parent with brown eyes and one parent with green eyes: 50% chance of baby with brown eyes, 37.5% chance of baby with green eyes, 12.5% chance of baby with blue eyes.

  • One parent with blue eyes and one parent with green eyes: 50% of chance of baby with blue eyes, 50% chance of baby with green eyes, 0% chance of baby with brown eyes.

Keep in mind that it may take six to 12 months for a baby’s true eye color to emerge, so the color you see at birth can certainly change.

SEE RELATED: Is it true all babies are born with blue eyes?

Predicting a baby’s eye color

While a baby eye color predictor or calculator you find online — some even includea baby eye color chart — can offer insights into whether your baby will have Mom’s blue eyes or Dad’s brown eyes, the forecasts they generate aren’t completely accurate.

That’s because the predictor or calculator relies solely on the parents’ eye colors, whereas a baby’s complex genetic makeup ultimately determines the color of their eyes. In the end, a baby eye color predictor or calculator may be fun to play with, but it doesn’t take into account the complicated science behind genetics.

Another tool you can use to help predict a baby’s eye color is the Punnett square. This square diagram lets you test different genetic combinations based on the parents’ eye colors — it also comes in handy when trying to figure out other genetic probabilities.

The Fertility Institutes offers an ethically questionable service: The organization claims to be the first and only genetics-based fertility program to offer high-level genetic screening of parents “seeking to have a voice in determining the eye color of planned children.”

“We are only offering eye color selection at this time in conjunction with our general genetic well-being and gender selection procedures. Eye color preference is available only as an ‘add-on’ procedure to our general procedures,” the Fertility Institutes says.

Most parents are more concerned with their children’s health and vision care than with their eye color.

Throughout development, infants and their eyes will experience many changes — beyond changes to their iris color. So, it’s important to visit a pediatric eye doctor who specializes in eye health and vision care for the wee ones.

READ NEXT: Most common eye color

Page published on Wednesday, March 3, 2021

Eye Color Genetics - All About Vision (2024)


Eye Color Genetics - All About Vision? ›

Two blue-eyed parents are likely to have a blue-eyed child, but it's not guaranteed. Two brown-eyed parents are likely to have a brown-eyed child. Again, it's not guaranteed. Two green-eyed parents are likely to have a green-eyed child, although there are exceptions.

Does the color of your eyes affect your vision? ›

Those with darker colored eyes experience less visual discomfort in bright, sunny conditions. Also, darker irises reflect less light within the eye, reducing susceptibility to glare and improving contrast discernment—so people with darker eyes may have better vision in high-glare situations, such as driving at night.

Which eye color has the best vision? ›

While lighter-colored eyes may be more sensitive to sunlight, they are not necessarily more sensitive to vision. In fact, blue eyes have better visual acuity than brown eyes. This means that blue-eyed people can see small details more clearly.

Do people with blue eyes have better night vision? ›

People with blue eyes may have better sight in dim conditions than those with brown eyes, according to LJMU research reported in New Scientist. The theory could explain why the colour has persisted in certain populations, for example in Northern Europe where skies are darker.

Is eye color entirely genetic? ›

The inheritance of eye color is more complex than originally suspected because multiple genes are involved. While a child's eye color can often be predicted by the eye colors of his or her parents and other relatives, genetic variations sometimes produce unexpected results.

What eye color is most likely to have bad vision? ›

As of now, the commonly accepted theory is that eye colour has no real effect on vision quality. It's significant to note that while people with lighter eyes may have increased light sensitivity, those with dark eyes should still make it a point to wear sunglasses whenever they set foot outside.

What is the rarest eye color? ›

While the global data on eye colors is limited, red and violet eyes are likely the rarest eye colors since they only affect a small group of people with albinism. But if you exclude eye colors brought on by albinism, then green and gray are likely the rarest.

Do purple eyes exist? ›

Although the deep blue eyes of some people such as Elizabeth Taylor can appear purple or violet at certain times, "true" violet-colored eyes occur only due to albinism. Eyes that appear red or violet under certain conditions due to albinism are less than 1 percent of the world's population.

What color eyes see better in the dark? ›

People with blue eyes can read better in darker conditions than those with brown eyes, a small study has found. This suggests having blue eyes is an advantage in low-light conditions, and might help explain why the trait evolved in northern Europe.

Why are green eyes so rare? ›

Only about 2 percent of people in the world have naturally green eyes. Green eyes are a genetic mutation that results in low levels of melanin, though more melanin than in blue eyes. Green eyes don't actually have any color.

What color eyes are more prone to cataracts? ›

The color of your eyes affects your risk of developing cataracts. Studies show that people with dark brown eyes have a higher risk of developing cataracts than people with lighter eyes. UV light is a known contributor to cataract development no matter what color your eyes are.

Are there any benefits to having blue eyes? ›

If you were born with blue eyes, there are a few benefits you might not be aware of:
  • Because less melanin allows for more light to pass through the eye, those with blue eyes can often tolerate longer periods of lower light.
  • Blue eyes appear to have a lower risk of developing cataracts than brown eyes.
Jan 19, 2023

Do blue eyes see better in snow? ›

Eye color can also affect your susceptibility to snow blindness; people with blue, green and light brown colored eyes are more vulnerable to photokeratitis. More than half of Americans have light-colored eyes, making snow blindness a significant public health issue.

Which parent determines eye color? ›

A child's eye color depends on the pairing of genes passed on from each parent, which is thought to involve at least three gene pairs. The two main gene pairs geneticists have focused on are EYCL1 (also called the gey gene) and EYCL3 (also called the bey2 gene).

Which parent carries eye color? ›

Babies inherit equal eye color genetics from both parents — 50% from each. From here, genes mutate to produce what are called alleles. Alleles are alternative forms of a gene that, in this case, are responsible for giving your baby a certain eye color.

Where do hazel eyes come from? ›

The way light scatters in hazel irises is a result of Rayleigh scattering, the same optical phenomenon that causes the sky to appear blue. Anyone can be born with hazel eyes, but it's most common in people of Brazilian, Middle Eastern, North African, or Spanish descent.

Which eye colour is more powerful? ›

They suggested that brown eye color is always dominant over blue eye color. This would mean that two blue-eyed parents would always produce blue-eyed children, never ones with brown eyes. For most of the past 100 years, this version of eye color genetics has been taught in classrooms around the world.

What eye color is the strongest? ›

The allele for brown eyes is the most dominant allele and is always dominant over the other two alleles and the allele for green eyes is always dominant over the allele for blue eyes, which is always recessive.


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