noun
sexual dimorphism
Biological term for physical differences between males and females of the same species beyond reproductive organs.
クジャクの羽の色は性的二形の代表例だ。
The color of peacock feathers is a classic example of sexual dimorphism.
性差 is a broader term for sex differences in general, while 性的二形 specifically refers to distinct physical forms between sexes in biology.
Compound of 性的 (sexual) and 二形 (two forms, dimorphism). The term is a direct translation of the English 'sexual dimorphism'.