It is also not the idea that is frequently paraded around when talking about a pay gap, since it can actually be argued against in sensible terms, for example, if women simply ask for raises less often than men, is that really unfair?

What more often than not happens is that the idea of a pay gap is presented as if women were earning less solely because they are women and their employers simply decided to pay them less for that reason. That is fiction and a whole bunch of us are tired of it, exhausted even.

It's also completely real that many women in their 20s and 30s, biologically, tend to not be available for work for maternity reasons. As an employer you have to include that opportunity cost of in the equation. Also, a woman in her late 30s - early 40s with two kids probably has a 2 or 3 year-hiatus when it comes to work experience compared to her male-colleagues.

I mean, all of those are heavily related to gender. And while you can frame them as "personal choice", that's only useful when analyzing an individual. When a significant part of the women make these choices that hurt their salaries and work prospects, one maybe should think about how society is influencing those choices, and turns out the vector is gender.

The defining quality is sex. Having children is simply more burdensome and time-consuming for women, no way around it (except artificial wombs in the distant future). I've advocated "child-bonus" before (i.e. paying companies extra when their employees get pregnant and on maternity leave), but I doubt that idea will gain any popularity.

When even in the most equal societies the sex-interest gap (which is upstream of career choice) not only persists, but increases, that is additional heavy evidence that it's influenced mainly by biology, not by society.

It's not unreasonable social calculus to just say "We the government are going to pay you your potential lost earnings, if you decide to have a child."

In the US at least, existing policy is mostly targeted at family units (via tax credits), which doesn't really bear on an individual's opportunity cost and decision to have children or not.

As for the results, I guess it's still early to tell: https://data.worldbank.org/indicator/SP.DYN.TFRT.IN?location...

Pregnancy is 9 months, the children live for many years. For that second part, men and women could take responsibilities in an equal way (save for breastfeeding, but pumps exists), but usually the burden tends to fall on the women and that hurts careers more than pregnancy.