In practice, people have pressures put on them from an early age to do whatever their elders think is best for them, and, frankly, their elders are often sexist, and the community they're born into might push them one way or another. This goes all the way up to the first year of university for many people.

There really isn't another good reason for a lot of what we see in terms of what people wind up doing (and some of how they behave while doing it!) when they're older, and we're well aware that socialisation during childhood is a powerful thing. As an example, there's relatively few people who are brought up without religion but find religion later - but there's a heck of a lot of people who were brought up with religion and never leave it.

Attempting to remove some of those pressures and counter-balance others seems perfectly reasonable, and unless there actually is something innate which causes boys to enjoy computers and girls to enjoy nursing, the result of that should be that we see a number of job markets level out to look like a reasonable cross-section of the population. Anybody who thinks that independent thinking is a good thing should likely support these efforts, or at least the well-implemented ones.