When it comes to the intricate web of genetics, each of us is a 50/50 mix of our mother’s and father’s DNA. But interestingly, some genetic traits are passed down exclusively from your biological father. From your smile to your hairline—and even your ability to father children—dad’s DNA has more sway in certain areas than you might think. Let’s explore six intriguing characteristics that science suggests you inherit solely from your father.

1. Tooth Shape and Alignment

You may thank—or blame—your dad for your smile. The alignment of your teeth is heavily influenced by genetics, and recent studies suggest a specific gene, known as the homeobox gene located on the X chromosome, plays a key role in tooth development. This gene is inherited from your father. So, if your dad had a perfect set of straight teeth or a row of crooked ones, chances are, you inherited similar dental traits. That said, factors like jaw size (which you can inherit from either parent), diet, and oral care habits also play a part in how your teeth ultimately turn out.

2. Hair Growth Patterns

If you’ve ever wondered why your body hair grows the way it does, your father might hold the answer. The androgen receptor gene—which influences hair growth and distribution—is another gene located on the X chromosome and passed down from the father. Though hair traits can come from either parent, scientists believe that many hair growth patterns, such as beard thickness or chest hair distribution, are more likely inherited from dad’s genetic input.

3. Baldness and Hair Loss

Dad’s genes may also affect whether you keep a full head of hair or experience male pattern baldness. This form of hair loss is linked to the same androgen receptor gene, and it’s a common genetic condition seen in many men. If your father has a receding hairline or thinning at the crown, there’s a significant chance you might follow in his footsteps. However, baldness isn’t guaranteed—it can come from either parent’s side of the family. If both sides have thick, healthy hair, you might just luck out.

4. Height

Height is a polygenic trait, meaning multiple genes contribute to how tall or short you grow. However, some research indicates that a father’s height may be a stronger predictor of a child’s stature. While both mom and dad contribute height genes, scientists believe certain height-related markers on the X chromosome—which is inherited from the father—play a bigger role. Still, genetics alone don’t determine height. Nutrition, sleep, and overall health during childhood also have a major impact.

5. Biological Sex

This one is fairly straightforward in genetics. Biological sex is determined by the sex chromosomes: females have two X chromosomes (XX), and males have one X and one Y (XY). When a baby is conceived, it receives an X chromosome from the mother and either an X or Y chromosome from the father. If the sperm carries an X chromosome, the baby will be female. If it carries a Y chromosome, the baby will be male. So, in essence, it’s dad who decides the baby’s sex.

6. Fertility in Future Generations

One lesser-known but important discovery is related to male fertility. Studies have shown that boys conceived through In Vitro Fertilization (IVF) may have a higher likelihood of fertility issues later in life. In other words, if a man was conceived using assisted reproductive technologies, he may also encounter difficulties when trying to father children. This insight is particularly relevant for couples trying to conceive and can help identify potential causes for infertility.

Final Thoughts

Genetics is a fascinating field, still full of mysteries even for the most advanced researchers. While we inherit traits from both of our parents, some features come exclusively from dad’s side of the family. From your dental structure to your chances of becoming a father yourself, your father’s DNA carries more influence than you might have realized. Of course, genes are only part of the story—environmental factors, lifestyle choices, and a little bit of chance all play a role in shaping who we are. So next time you find yourself inspecting your smile in the mirror or noticing your hairline in photos, you might have your dad to thank for those unique features. Understanding these genetic hand-me-downs not only connects us to our family lineage but also gives us a deeper appreciation of what makes each of us truly one-of-a-kind.