"...the elementary teachers got paid less and teaching younger grades was not viewed as prestigious so men didn't want those jobs." Thanks for this, RonsterG. Think you've got it. 

My experience exactly...in broadcasting. Go back to the late 60s and early 70s--and I can--to witness what happened.  Radio station owners/managers realized they could earn societal brownie points by hiring young women on-air---BCIT, Ryerson, Mount Royal et al were pumping out female broadcast grads anyway.  Moreover, they could avoid big wage hikes (to big egos) by doing so. The "prestige" slipped away...

I saw the feminization of  a male enclave.  Just stating the obvious, no gender-bashing intended.  I still hits me, but doesn't hit anybody under 40: I watch TV news and play a little game: count the number of male "journalists" doing interviews or offering on-the-scene comments.  Easy to do...usually on one hand.  Go to CBC TV archives; listen to old tapes, watch vintage footage: NO women at all.