History of the Parental Advisory Explicit Content sign

I believe that many people noticed this sign on the covers of the albums or singles of their favorite artists, and everybody knows what it means, yet a few know its history.

In the 80s, a woman, Tipper Gore-her name will be mentioned later-bought her daughter Karenna an album of the artist Prince "Purple Rain", but then having heard the content of the singer's lyrics, she was extremely unhappy because it mentioned "masturbation".

So, in 1885, along with 3 other women, they create the Parents Music Resource Center - PMRC and made a list of 15 songs, so-called "Dirty Fifteen", that had an adult context. After that, they demanded the RIAA do something, after which the first version-phrase appeared:
Explicit Lyrics: Recommendations for Parents

As for its criteria - there are simply none. There are so many different stylized signs that can be seen on the covers. The only requirement is to include it in case of swearing, sexual and racist themes.