Career progression is the most insidious and overlooked barrier here. Unless you take an equal amount of time off —ie the partner takes more time than the moth

Career progression is the most insidious and overlooked barrier here. Unless you take an equal amount of time off —ie the partner takes more time than the mother— the partner's career will progress more in that time, earning more money by the time they come back to work. This means it less likely that the partner will take equal time off next time, skewing the amounts even further. Iterate this loop a few times and you open up a real gulf in take-home pay. So much so that it becomes an unignorable factor in decisions about childcare and schooling that can end up with mothers taking years out of full-time employment. All because their partner worked more the first time. And that's all running on the unrealistic assumption that women don't get [illegally] passed over for promotion just because they have a functioning uterus. Why would you promote Janet over Jim if it's likely that she's going to take 6-18 months off to start a family, and maybe never return? That can upset the scales well before a baby enters the scene. --- On a personal note, we have two children and I've long earned less than their mother so we're lucky that we don't have to consider this stuff in these terms. She's taken time off and while it's hurt her against her colleagues, our balance is much fairer than many relationships. And I feel privileged to have had such significant input to my children's education and upbringing.