Are all my traits decided by genes?
No. Genes influence almost everything about you, but for most traits the environment matters just as much.
Some traits are strongly genetic — eye colour, blood type, certain diseases. Most everyday traits, like height, weight, personality, and risk for common illnesses, are a mix of many genes plus your environment and choices.
Height, for example, is largely genetic but still depends on childhood nutrition. The honest summary for most traits: genes load the dice, life rolls them.
Last reviewed 29 May 2026 · reviewed by someone with genetics training