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Most people have two distinct eyebrows, with a more faint type of hair between their brows. But in some people, this hair is thicker, more like eyebrow hair. And this creates the appearance of one long eyebrow—a unibrow. Although the knowledge science currently has about the inheritance of unibrows is limited,  AncestryDNA can tell you if your DNA indicates that you may have a unibrow. 

Man with unibrow genetics

More About Unibrows

Throughout history, eyebrow styles have changed, with fashion dictating how people have shaped and groomed their eyebrows, including unibrows. This varied from penciling in a unibrow to plucking the brows completely. 

In ancient Greece, having one eyebrow was considered beautiful. Desirable and intelligent women had them. Rich Greek women would paint unibrows if they didn't have them naturally. 

In the Middle Ages, women wanted to have a large forehead, so they shaved or plucked their eyebrows. 

Today some cultures value the one-eyebrow look. In Tajikistan, for example, women use a leafy herb called usma to paint unibrows. 

The Genetics of Unibrows

Whether or not you have a unibrow is only partly due to your genes. Other things like grooming can influence how your eyebrows look and how they grow. Plucking and waxing, for example, can permanently change your eyebrows.

Scientists have identified a gene that appears to influence whether or not your eyebrows meet in the middle: the PAX3 gene on chromosome 2. There is a difference in the DNA that seems to correspond with varying degrees of unibrow.

There are other genes science hasn't yet identified that influence eyebrow shape and thickness. As we learn more about the genetics of unibrows, there may be a better predictor for this trait. 

The Science Behind Unibrows

Can Mom or Dad take credit for how close your brows come together? They can indeed—at least partly. Each of your parents passes a copy of their PAX3 gene down to you. Which version of the gene you get from each parent can help determine whether or not your eyebrows meet in the middle.

And just because you have thick hair on your head or a dense beard doesn't mean you’ll have a unibrow. The genes for eyebrow thickness, beard thickness, and hair type are different. So you can have thin hair on your scalp and thick eyebrows that grow together in the middle. Or you can have thick hair, a heavy beard, and sparse eyebrows.

Interesting Facts About Unibrows

Unibrows may seem more common in men, but they happen in both sexes. In much of the Western world, women are just more likely to remove the extra hair. 

There are a few well-known examples of celebrities with unibrows. But perhaps the most famous unibrow in history belongs to Mexican artist Frida Kahlo, whose unibrow featured prominently in her iconic self-portraits. 
Eyebrows serve an important biological role, keeping sweat and rain out of your eyes. They also have symbolic roles. Some cultures think the unibrow is good luck. And some consider it a sign of fertility. 

What does your DNA indicate about your eyebrows and the presence of a unibrow? AncestryDNA tests for a range of appearance and sensory traits that can give you new insight or confirm what you already know.