First, we know this lead to an end of the cultural/religious practice of "waiting till you are married to have sex." The creation of the birth control pill is the defining scientific change most involved here. Which logically also lead to a lot more competition between men for women who are no longer economically dependent on them for financial security and child support. This basically introduced chaos in the male realm of society. Suddenly, if you're poor, socially awkward, discriminated unfairly against, or unattractive (or all of the above) a woman doesn't need to settle for you early in life or ever. This is basically a breeding ground for the development of violence between males to secure more resources and social capital than they can overwise secure without said violence.

By delinking humans from a core biological fact, that sex has real consequences, we have essentially created practically a new human species and now require unique cultural strategies, such as redistribution of wealth, to help mitigate this problem to whatever extent we deem wise. Legalization of prostitution or abortion is therefore reactionary instead of simply informed by changes in reason or moral judgment. Punitive measures are now required against men who refuse to support their children at all, often to multiple women, whereas in the past social dogma and pressure sufficed to maintain order, and ostracization was feared far more.