Shortly after their formation in April 1985, the Parents Music Resource Center (PMRC) assembled a list of fifteen songs with deemed unsuitable content. Particular criticism was placed on "Darling Nikki" by Prince, after PMRC co-founder Mary "Tipper" Gore heard her 11-year-old daughter sing the lyrics, which included an explicit mention of masturbation.[1] The Recording Industry Association of America (RIAA) responded by introducing an early version of their content warning label, although the PMRC was displeased and proposed that a music rating system structured like the Motion Picture Association of America film rating system be enacted.