Schoolmaster used to be as honorable a calling as schoolmistress. Sometimes boys need a man around to keep them under control.
And not just keep them under control but give them a positive, masculine male role model (if they don't have one at home) and also to distinguish between truly destructive behavior and little boys acting like little boys.
Uh, we're talking first and second grades here. Most low-grade teachers have been women forever (there are actually more male low-grade teachers today than back in the 1950's). Most male teachers in those days were in junior and senior high schools (where they ARE needed). And kids (both sexes) learned to read and write without problems.
The problem isn't the sex of the teachers, it is the change in teaching methods, from stuff that works (phonics), to "ed biz" politically correct mush that turns out uneducated dolts, and the failure to allow any kind of real discipline for misbehavior.
Case in point. A young adult (apparently just out of high school) was canvassing our neighborhood looking for part-time work. I asked him to leave his name and phone number, and his writing on the resultant paper looked like a first-graders scrawl.