Fair enough, point taken. It just feels like this is one of those issues that everyone devotes much ideological pontificating to, without formulating concrete strategies.
You suggested: I'd raise taxes on the rich, the money to be spent on improved provision for everyone, including specifically kids and parents.
Now that sounds great to me, I'd vote for you, but how specifically would that address the gender pay gap? Might it not just raise standards all round, whilst perpetuating any structural imbalances that exist? If a woman takes time off to have children, and a man doesn't - and also does not avail themselves of any of your improved provisions, such as better access to flexible working - they will, most likely, still end up being paid more.