Peterson's 12 Rules For Life, have you heard of this?

[Amarok]

Learn about correlation.

I'm well aware of correlation now for causation

It's clear that women are paid less. It's not clear the exact degree to which they are paid less because they are women.

It's pretty clear when you stop making excuses

There are several things about women, taken as a population, that make them different than men-- personality traits (i.e. kindness, aggression, etc.), reproductive roles and timing, different interests, and so on.

All of which begs the question if they are inherent traits or taught cultural traits? are they reproduction roles as a culture or as inherent  to sex? are those interests that are natural or imposed ?and so on . None of this makes his case nor refutes an underlying cultural idea's about them being women as the  source of the pay gap .