In the 1950’s the ‘pin up calendar’ was edgy and barely (no pun intended) legal. Now its mainstreamed as a fundraising tool and published as the “Body Issue” of “ESPN Magazine.
The standards legally regarding what is ‘pornography’ were lowered by the courts over a period from the late 1950’s into the 1970’s when anything goes reigned for a bit then standards were tightened up a little to make child porn illegal.
About the same time underdeveloped women (18 but looked like 12) were supposed to be 'sex' objects, something which likely appealed to pedophiles and homosexuals alike.