This disparity has been ongoing for a number of years. I even remember when the book lists changed a fair bit to this sort of thing, if you can believe it.
In any case, I can remember when as a kid in grade school, the books we read had heroes and heroines, but slanted more towards the men. As I got a little older (think about 5th/6th grade) and the ERA movement became so prevalent, the book lists and such changed (for lit classes and whatnot), with the focus becoming more so towards strong women, but nowhere near to the degree it is now. If I asked my mom about it, I'm sure she'd tell me the high school lists were vastly different from when I was in high school, and she was in high school. I noticed that the book lists changed AGAIN when my own children were in school.
So, how to fight such a thing? It takes proactive PARENTS who take a genuine interest in what their children are reading. It also takes a parent who encourages a child to have a broad area of reading interests, not focusing on just what the schools say they can and cannot read for class. I was lucky in that respect. My parents never agreed with the published school book lists, and encouraged me to read whatever I enjoyed within reason (age appropriateness applied ). I did the same with own kids (funny how you apply to your own what your parents did with you). But, that's just a small drop in the bucket, so to speak.
Regardless of WHEN in time you're talking about; in education, those book lists for allowed reading have always been a bit skewed. Whether to promote an administrator's personal views and beliefs, or whatever. They've certainly never been tailored to an individual CHILD'S needs.