Since exploding from the streets of New York in the 1970s, the cultural phenomenon known as hip-hop has morphed from hard-driving dance numbers into sex- and violence-filled "gangsta rap" — and a record-label goldmine. Gangsta lyrics have sparked periodic outbreaks of indignation, but the outrage intensified after white shock jock Don Imus was fired in April for describing black female athletes in the degrading terms used commonly by hip-hop performers. African-American leaders, including Bill Cosby, Oprah Winfrey and the Rev. Al Sharpton, claim the genre's glorification of thug culture — often for the entertainment of white youths — drags down the black community. In response, a few top hip-hop figures have called for cleaning up gangsta content. Meanwhile, a school of socially conscious hip-hop remains vibrant, embraced by political activists, school reformers and artistic innovators who call it an inspiration no matter what happens to the gangsta style.