na-adjective
genetic; hereditary
Used in scientific, medical, or general contexts to describe traits, diseases, or characteristics passed down through genes.
この病気は遺伝的な要因が強い。
This disease has strong genetic factors.
遺伝的に決まる特徴もある。
Some traits are determined genetically.
先天的 means 'congenital' or 'innate', present from birth but not necessarily genetic. 遺伝的 specifically refers to genetic inheritance.
Compound of 遺伝 (iden, 'heredity') + 的 (-teki, '-like, -ic'). 遺伝 is composed of 遺 (i, 'leave behind') and 伝 (den, 'transmit').