That might be one reason. The woman has to take some time off, but the difference in lost opportunities between 12 and 18 months is not so much, whereas the difference between 0 and 6 months could be quite a bit if the man decided to take some of the parental leave (and there may well be a working culture where the man is legally entitled to take parental leave, but if he does take that option… I’m really not sure, and I’m not denying that viewing the household as women’s work is a significant factor either.
As far as I’m concerned, if we had been allowed to take one year of parental leave to share out as we wished, we would probably have split it about 11.5 months/0.5 months. It’s good for me to be there at the start, but it’s not my body that needs to recover and it’s not me who has to spend a lot of the day breastfeeding the baby for the next year or so. If we had been given two years, I’d probably have taken 2-3 months off. If I had taken equal leave, we’d have had to find childcare after one year - I’m not sure if that would be optimal for a young child given the choice, and it could really add to costs and hassle without providing any great advantages. Now that our daugher is a couple of years old, I work from home and look after the kids while my wife is focusing more on her career.
I do think that this is an area where rational decisions are made that have a predictable and unequal effect. We’re not competing with each other and neither of our careers are our first priority, but we make decisions that we consider to be the most beneficial to everyone. With only one child, this probably wouldn’t have a huge effect in itself, but if we followed the same reasoning and had five children, there’s no way she could compete with men on an equal level in the workforce. I could take more time off to even the odds, but I would only do it if it was the best thing for the family, not so that I could take a hit for feminism.
There’s also the fact that men generally marry women who are a few years younger than them, and therefore often earn less. If one person has to temporarily put their job aside for the family, the rational short-term choice would generally be the one who already has to take time off to recover, who is also earning less and who often has more experience with domestic tasks and childcare due to already having taken essential time off. And so the trend goes on.
Sometimes this issue seems quite related to the main topic: often I get the idea that the language of equality is focused on a concept of individual success, where a higher salary and certain other markers are seen as being the benchmarks to aim for. Women are disadvantaged because they have to stay at home, look after the kids and do housework, while men are able to live the dream of spending all day at work in exchange for money. I think it is often the case that women are being held back, but I think we lose something if we make corporate goals the ideal. Many countries that allow more parental leave don’t actually end up with a statistically more equal society, but in my experience they do seem to have more cooperation by men in childcare and domestic work and more respect for these skills. I want women to be able to progress in their careers, find job satisfaction and earn high salaries, but I’d prefer to see a society where neither men nor women felt that they had to do this in order to live a good life.