Red hair and green eyes is a combination that’s considered rare. The chances you or your child will have it are based on whether your immediate family members had red hair or green eyes, though it can skip generations.

Having red hair or green eyes (or both) all comes down to your genes. Your genetic makeup is based on a combination of markers your parents have passed to you.

While having red hair and green eyes isn’t common, it’s also not impossible, especially if there’s a history of the combination on both sides of your family.

Red hair and green eyes together is a particularly rare occurrence. Both traits are the result of recessive (uncommon) genes, just as blue eyes or O blood type is.

While the odds of having red hair and green eyes can’t be guaranteed, it’s interesting to look at the genetics behind these rare occurrences. Each person’s DNA includes 20,000 genes, just a few of which dictate hair color and eye color.

Your hair, skin, and eye colors are all dictated by your genes. These genes are passed to you by your parents, just as their genetic makeups were passed to them by their parents.

When it comes to hair and eye color, some genes are more dominant. This explains why brown hair and brown eyes are far more common than lighter colors.

However, a person with dark hair or eyes who has family members with either red hair or green eyes can still carry the genes for these variations — these types of genes are recessive.

Recessive genes are genetic markers that aren’t as common as more dominant ones. Red hair and green eyes are separate recessive genes, and incidences of both traits occurring together are even rarer.

Having this combination isn’t based on just one gene. For you to have red hair and green eyes, your parents would both need to carry at least one recessive gene for each. However, both your parents having these genes doesn’t guarantee you will have them.

One study found that the red hair-green eyes genetic combination is one of the rarest, at -0.14 correlation. Having red hair and blue eyes is even rarer. It may be more helpful to look at the odds of each trait separately.

If both parents carry these recessive genes, there’s about a 50 percent chance their child will have red hair. The color of your hair is dictated by melanin, the same color-producing group of cells that’s responsible for your skin color.

Redheads have a melanocortin 1 receptor (MC1R) mutation, which makes their melanin production lighter. With an MC1R mutation, you’ll have more pheomelanin cells, which produce red hair.

Predicting eye color is slightly more complex. An estimated 16 genes dictate your eye color, and only two of them, located on chromosome 15, determine whether you’ll have darker or lighter eyes.

Having red hair and green eyes isn’t necessarily dictated by your sex. Each occurrence (hair color and eye color) is instead programmed in your DNA by the genes you carry from both your parents.

Still, some research has suggested that red hair is more common in women than in men.

Red hair is most commonly associated with Ireland. Still, not everyone from Ireland — or everyone with an Irish bloodline — will end up having red locks. Red hair is also historically seen in other countries in the region, including Great Britain.

Recessive genes that dictate lighter eye color are most common in Scandinavia. Countries in this Northern European region include:

  • Denmark
  • Finland
  • Iceland
  • Norway
  • Sweden

Based on this fact, you might see more green and blue eyes in this region than brown eyes, which are linked to more dominant genes. However, this doesn’t mean all people from Scandinavia have lighter eyes.

From a health perspective, it doesn’t matter where you live if you have red hair and green eyes. One possible exception: If you have a lighter skin tone (which is common in redheads), living closer to the equator could put you at greater risk for UV exposure and related skin cancers.

It’s a fact that the combination of red hair and green eyes is rare. As with any uncommon trait, myths about certain hair and eye colors abound, especially on the internet.

Some of the most common myths about people with red hair and/or green eyes are:

  • reduced tolerance for pain (although one study found red-haired women are more sensitive)
  • easier bruising, which may be linked to fairer skin tone making injuries more noticeable
  • more prone to cancer — research has shown red-headed women might have a higher occurrence of cervical, colorectal, ovarian, and uterine cancers, but there’s not an established direct link between hair color and cancer risk
  • a bad temper (hence the stereotype of having an “Irish” temper)
  • a longer lifespan (for people with green eyes)

Due to genetic complexities, there’s not a clear-cut way to determine your chances of having a child with both red hair and green eyes.

While it’s slightly easier to determine the odds of having red hair, green eyes are more difficult to predict.

The best way to predict a child’s genetic makeup is to look at each parent’s genes. It’s also possible to get more information via genetic testing. Keep in mind that children with the same parents can have different eye and hair colors.