I'll risk downvotes to create a discussion in a sometimes touchy subject.
STEM fields aren't the only ones with large gender imbalances. Others include elementary school teaching, nursing, garbage collecting, road maintenance, and many others.
Are there efforts to recruit men to become elementary school teachers on the scale to promote women in STEM field?
Are there efforts to recruit women into construction and collecting garbage?
Why or why not? I don't have the answers, although I don't think male-only scholarships exist to promote male teachers (though I think society would benefit from it) nor female-only apprenticeships to promote women going into construction or garbage collection (though I think society would benefit from it, and would probably result in making the fields safer).
I'm curious what people say. If nothing else, if we find successes in some areas we may be able to replicate them in others.