Contrary to what popular opinion would have you believe, women were in the workforce long before the '70s, and they were making equal pay to men. At least if they were union members.
Most of the big industrial plants around Guelph, K-W, Cambridge where I came up employed lots of women on the shop floor back in the sixties. When I worked in Mr. Irving's shipyard in the '90s we had women electricians, women pipefitters, women welders. There was absolutely nothing in the contract that said a woman was to be paid less.
Some of the old-timers at Saint John Shipbuilding recalled the era when women in the trades were a novelty. There was harassment and sexism. To the credit of Mr. Irving, the dinosaurs who didn't want to accept women on their work crew were dealt with ruthlessly.
As in they found themselves unemployed in short order.
The local school board, 100% unionized, has complete gender parity in their pay scale. In fact, they've got almost twice as many women in the $100,000 plus category as they have men.
The folks who are whining about women only making 70% of a man's paycheque obviously never worked in a union environment.