Vietnam war and the Pill, maybe making women think twice about populating the world with more canon fodder. Also possibly US going off the gold standard had some effect.
Discussion
Going off the gold standard absolutely had a huge effect. Ever since then debasement has decreased the standard of living and increased the cost of living, including raising a family and all the associated bills. Anti family propaganda has played a large part of well. None of that would be as effective without bad money.
www.wtfhappenedin1971.com