Tech industry demands long hours, and most women in Tech are married to men in Tech, and by the time they are in their 30s and want to have kids, there is no need for them to have two salaries. In other industries, women are given a break if they choose to continue working after having kids, but in exchange they don’t receive promotions and are expected to spend more time at home with the kids. I have met many women who work in tech and almost none of them have kids, but I can tell some of them would like to. If they get the opportunity I imagine they would just quit.