Who is credited with starting the 'Gangsta rap' subgenre?

N.W.A is credited with starting the 'Gangsta rap' subgenre primarily due to their impactful album "Straight Outta Compton," released in 1988. This record was revolutionary in its portrayal of life in the inner cities of America, highlighting issues such as violence, police brutality, and the realities of street life. Their raw, unfiltered approach to lyrics not only defined the aesthetic of gangsta rap but also set the tone for future artists in the genre.

N.W.A's sound was characterized by aggressive beats and street narratives, which resonated with many listeners and influenced the direction of hip-hop music significantly. Their work laid the foundation for many elements that would become staples in gangsta rap, such as explicit content and a focus on authenticity regarding life experiences. This pioneering effort established N.W.A as a landmark group in the evolution of popular music, making them the key figure in the inception of gangsta rap.