A woman who has two children, at minimum, works two years less. In a (25 - 65) yr career that's a 10% pay gap she'll experience wrt a male who works the same period.
The paygap is just a dial which controls the rate of motherhood.
There is no "per job" paygap. Nor could there plausibly be. For if any group could be paid less to do the same work, someone en mass would be, thus lowering the pay for that work. (Its unclear how such a rich source of free output from 50% of the population could go untapped, systematically).
Though even if that logic isnt persuasive, there is no measured per-job pay difference at an individual level. The "pay gap" describes a mean difference in pay at population level -- when you control for total hours worked, it disappears.