There are no "gender classes" at the high school level anywhere, that's a myth peddled by the Right to drum up fear among their base.

In terms of what they would supposedly take instead, it's probably STEM related. A lot of people on both sides of the political spectrum have been pushing STEM in schools for a long time to the detriment of the arts and humanities, because it's seen as a more directly profitable skillset. What you lose, of course, is a well-rounded education, though many people don't seem to care.