We have the data on the average hours women work, it's ~1mo/yr less. We also know the pay gap, its 1mo/yr. The effect due to differential pay is a rounding error.

We can also do the simulation trivially using empirical data, women on average in the UK have 2 children, and take four years out of work to have them, and when in work, work for 9 years part-time. That creates a theoretical paygap of 20% on a 40 year career across male/female populations

The claim that the economy sustains a free markdown on 50% of the population's labour is mad. What force of nature is keeping a mass of businesses forming just hiring this cheap labour? Why arent there businesses booming hiring, en mass, women?

Either way, aside from that madness. The effect is, to a significant figure, entirely explained by working duration not differential pay.

And I've personally known no mothers who think the population of women is better served by reducing their part-time work, and having them work more.