"I fail to see why we should move the goalposts for women to take account of children."
Really? You fail to see why the world should be organised so that men, women and families can function as families, parents and workers all at the same time? So you are in favour of work and family life always being in conflict and very hard to balance? Why? Are you Blackadder's aunt or something, why would anyone want to organise society so that it is as difficult for the majority of people to function as possible?
I suggest you read the Equality Illusion by Kat Banyard if you think we have equality.
There is still a pay gap. Women still do work at a lesser rate than men.
Men still have more leisure time than women. Women still do most of the housework and childcare even where they do the same amount of paid work as the men they live with.
Men don't get raped or sexually assaulted at the rate of 1 in 4. Women do.
Men don't get repeatedly assaulted by their partners at the rate of 1 in 4. Women do.
Men don't get killed at the rate of 2 a week by their partners or ex partners. Women do.
When men are raped, they are not automatically assumed to be lying. Women are. They aren't asked what they were wearing. Women are. They aren't asked if they led the man on, gave him consent signals in the run up to the rape. Women are.
When men are single parents, they are admired and lauded as hardworking heroes. Women aren't.
If more men want care and control of their children in the event of a relationship breakdown, there is a really easy way of getting it - do more of the childcare. Courts award care and control on the basis of who has done the childcare and who has spent more time with the children and attended to their day to day needs. If men did more of that, they'd start getting more care and control of their children. And their relationships would be less likely to break down in the first place anyway, I'd suggest.