While only 30% of active physicians in the US are female, the gender split among residents (entering the profession) is close to 50%/50%.
I will comment, that it seems easier for women to move "up" than for men to move "down." It seems like there is more friction against male nurses/dental assistants than there is against women doctors/dentists.
Honestly, men really should consider these fields. In SF, the median pay for a dental hygienist is almost as high as for a software developer, and median pay is actually higher for a registered nurse (again, in SF, this isn't the case nationally) [1]. Nursing and dental hygiene have less upside, but less age discrimination and better career stability.
If you'd like more career flexibility, would like to be able to work part time, step back from the career track to take care of kids, and get back into it later, dental hygiene and nursing are probably better than software development. This is particularly important if you'd like to be able to have kids and spend time with them, while keeping stable employment and/or not badly harming your future prospects of employment.
[1] US news "best jobs", drill down to pay by region, will provide a summary of BLS data.
Is that really about gender these days? As a patient, I see it that way too. But that's because the doctor has significantly more education and training.
I guess it would depend on the occupation. For example, I don't see much difference between nurses and doctors in terms of something that could be quantified as a gender-specific preference. It seems to me that the idea of "nurses are women, doctors are men" came about more from the idea that women were "too stupid" to be doctors and that it was a "man's job." Even today many doctors look down on nurses (as 'below' them; people whose opinions don't matter), and men that decide to become nurses also face a uphill battle of social acceptance.