Under what basis? there are many theories to this.
In response to the OP's question - the physiology between men & women... or metabolism/endocrine function differs significantly. It's a testosterone versus estrogen 'thing'. The androgenic effects of testosterone promote the secondary sex characteristics in men; including growth, facial hair, etc, etc... upon reception of T to the AR... or reduction of T to DHT via 5a-reductase to promote greater androgenic effects... while estradiol, a biologically active form of estrogen to promote the female secondary sex characteristics do not promote the similar changes in women as androgens/testosterone do in men.
In essence, it is an evolutionary basis, but it is a role played by the Hypothalamic-Pituitary Gonadal Axis..
