It all started with Murphy Brown, Dan Quayle was right and years later Candace Bergen basically admitted that Quayle was right.
It didn't start with Murphy Brown. The real exponential explosion in illegitimacy rates--both White & Black--came with the agitations in the late 1950s & 1960s. I tracked the social breakdown in that era, and published articles on it.
The most obvious cause was the Egalitarian bias in American Education, which taught children that the older members of their families' thoughts on proper behavior were rooted in "prejudice" and could be safely ignored. The process can be described as "trashing grandma," and served to "free" young women of both major races, from standards of behavior that had favored traditional marriages as opposed to promiscuous breeding.
William Flax