When did "bitch" start applying to male and females outside of gay community?

It used to be that women were called bitches and men were called bastards. Now both men and women are called bitches. When did this trend start?

• When males and females outside of the gay community started acting like BITCHES.

• August 3rd, 1988

• Does it have anything to do with the term "bastard" becoming outdated? I mean, being a bastard is no big deal anymore.