So much of your appearance comes from your ancestors. Some traits, like dimples, cleft chins, and skin pigmentation, are easy to notice if you've inherited them from your biological parents. The genetic influence on other characteristics, like whether or not you have flat feet, isn’t so obvious.

If you're flat-footed, there's a chance that something in your genetics contributes to it. The results of an AncestryDNA + Traits can help suggest what your genes reveal.

What Are Flat Feet?

Commonly diagnosed as pes planus, flat feet occur when one or both feet have little or no arches. While all babies are born with flat feet, most develop arches as they grow and begin walking. This arch development supports bipedal movement. When walking, with every step, foot arches create stiffness in the feet that helps transmit force. At the same time, foot arches also remain flexible enough to store and release mechanical energy like a spring.

Some people with flat feet never develop arches. Others experience fallen arches—feet that formerly had arches, but over time those arches flattened.

Flat feet typically fall into one of these categories:

• Flexible: Most people have this type of flat foot. When they sit or don't have weight on their feet, their arches appear prominent. However, as soon as they stand up, the arch disappears.
• Rigid: Rigid flat feet are rarer. Those with these types of feet lack arches when sitting or standing.
• Congenital: Some babies have a condition or genetic anomaly that causes them never to develop an arch.
• Acquired: People whose feet lose their natural arches with age or time may be described as having fallen arches or progressive collapsing foot deformity (PCFD).

An estimated 20-37% of the population has some degree of flat-footedness. While not everyone with flat feet experiences problems, flat feet can cause pain in the heel or arch, especially while you’re active. They can also cause swelling on the inside of the ankle.

If you have flat feet, there are simple ways to help combat any discomfort:

• Try a different style or size of shoe.
• See if arch-support inserts help.
• Practice focused exercises and methods of stretching.

Genetics and Flat Feet

Studies acknowledge the significant influence genetics have over flat feet. To dive deeper into the genetics of this trait, the team at AncestryDNA conducted a genome-wide association study of flat feet. The team asked 750,000 participants, "Do you have flat feet?" When the scientists at AncestryDNA compared participants’ answers to their genetic profiles, they found that 200 DNA markers could be related to pes planus.

To further expand upon these findings, the team calculated a polygenic risk score, a statistical tool to predict how likely you are to have flat feet based on your genetics. Together with these results, the team determined having flat feet is at least 6% genetic. Because the human genome is so complex, the real genetic influence on flat feet may be much higher. However, external factors also impact this trait.

What Else Does Science Say About Having Flat Feet?

Science points to many reasons an individual might have flat feet, including aging, obesity, and injury.

Several studies have highlighted the role obesity can play in developing flat feet, especially in younger individuals (11-23 years old). This acquired version of flat feet can occur because excess weight changes gait mechanics while walking and adds extra strain on the foot's muscles and ligaments, which are responsible for maintaining the foot's arch. As the structure weakens with time, it can change how someone walks and result in flat feet.

Other factors can also cause flat feet to develop, sometimes even in just one foot. Injuries and illnesses that attack the tendons can cause flat feet. Aging may also contribute to the development of flat feet. As you age, your body becomes less resilient and often loses strength. This normal, natural change in the body can result in wider feet and collapsed arches.

Interesting Facts About Flat Feet

An estimated 2.5% of the population has an extra bone—an accessory navicular—in their feet. This congenital feature often goes undetected unless it causes symptoms like flat feet.

Specific life events also cause your feet to change. For example, hormonal changes during pregnancy can contribute to ligament laxity, while weight gain can cause extra pressure on the feet. Plus, the shift in a pregnant person’s center of gravity may lead to gait changes. The combination of these factors often contributes to broader, flatter feet, which can make shoes feel tighter.

If you're flat-footed, have flat-footed relatives, or are curious about your genetics, AncestryDNA + Traits can provide insights into a variety of traits. With one simple test, you can learn about 80-plus traits related to personality, appearance, and performance. If you've already taken a test, your results are ready to review with an Ancestry membership.