That's because western medicine is based on ancient Greek medicine, where women formed their own bodies of medicine for childbirth separate from the male doctors. The male doctors were HEAVILY involved in the military, so much of their medicine was written down and preserved. A lot of women's medicine did not survive the Dark Ages for this reason, so medicine as a default became synonymous with "men's medicine." That's also why the birthing position changed for women - men took over their medical jurisdiction over childbirth.