Why is this specific to females? This happens to males indirectly. Unless your fabulously wealthy and can basically hire a 25 Y/O wife/Surrogate Mother, most men have steadily declining chance to have a child as they get older too. Simply because the available pool of fertile females willing to have a child with them is declining.
That is not even to mention actual biological problems that make men functionally infertile. So while its technically possible for men to have children until they are dead, realistically a large number are loosing their fertility as well. I know couples in their 30's/early 40's where it turned out to be the male causing the problems.
I think it's implied that it's easier for men to have children and not drop the ball on the career; so they don't need to wait until they are old.
A newborn is a much bigger disruption for the mother than the father. This is biological but also cultural (e.g. in some EU countries only women get a months long paid vacation after birth).
Maybe.. OTOH, in the US it seems the common expectation these days it that men pull their weight when it comes to raising children. God knows I would have gotten divorced if I continued to work till 10PM leaving my wife at home with a young child.
Which maybe, if the man is ok with biologically having a child they see a couple times a month that works, otherwise most men are going to be up feeding the baby all night long too, and picking them up from school, staying home to take care of them when they are sick.
So, just the split work/family focus is going to remove most men from the competition to be top dog at the office unless they are successful enough, and can find a women willing to be a housewife.
Women can probably pull this off in reverse if they are successful enough, and find an "artist" or someone already outside of the traditional male career paths too. Biologically its not unheard of for women to work until their due date and then return to work in a week or so, leaving the child with a caregiver (frequently an aging parent/etc).
Of course if she wants to participate in the child's upbringing the split focus issues will likely arise too.
Hence my comment that to imagine this is strictly a female problem is an oversimplification. Yes, the problems are slightly different, but to imagine a man can work his way up to some level of success and then find a younger woman willing to be a housewife to a 20 year older man is a risky proposition too.
That is not even to mention actual biological problems that make men functionally infertile. So while its technically possible for men to have children until they are dead, realistically a large number are loosing their fertility as well. I know couples in their 30's/early 40's where it turned out to be the male causing the problems.