men are more likely to be in STEM because there are more smart men than smart women
there are also more dumb men than dumb women though, and more women tend to have average intelligence than men
obviously more men being in STEM is going to result in a "pay gap" because they get paid more than women, but yet women hold 51% of the wealth in the united states, implying that the men with STEM jobs tend to share their wealth
basically, the pay gap is a f**king myth