Are physical traits entirely determined by your DNA?

No, not entirely!

Traits like hair colour, height, nose size, eye colour, etc. aren't "entirely" determined by your DNA code… they are influenced epigenetically as well - for example, the mother's diet and stress levels during pregnancy are a huge factor.

Also identical twins with the same genetic code start looking different as they grow up, which shows that diet and environment also influence the expression of your DNA.

It's also worth noting that things like your body weight, how healthy you are, or your risk for disease, are "influenced" by DNA (nature), but you also have environmental influences that affect those traits and who you are.

So saying that who you are is "entirely" determined by your DNA is not a fair statement, although scientists used to believe that - until they discovered the epigenetic influences from the environment (what you eat, whether you exercise, the air you breathe, and so on) on how your DNA is expressed.

So, we are not destined or doomed by our genes.

You'll be learning more about this in the next modules!

AUTHOR: Alex Ruani, Research Director

Updated on: 14/10/2026