matriarchy leads to promiscuity, promiscuity amplifies the tournament mating dynamics of humanity, and women select for the strongest most masculine men. this leads to a relative shift towards a more masculine appearance. whereas patriarchal cultures, whether monogamous or polygamous, see this effect reduced. male-dominated polygamy (common in east asia) accentuates this even more because the emperor/his nobles get free selection of women, they select for more neotenous features, and their children are more likely to survive.
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