Wellfare babies have supposedly been a thing for decades. I don't know of any good stats, though. There might be a financial incentive against marriage if getting married doesn't double whatever income limit there is.

I have heard estimates that the value of all government subsidies, assistance and incentives for poor families is around $80k /yr (probably higher now). So there is a financial incentive to not work unless you get paid $80k after taxes. It doesn't quite work that way, though. Most assistance programs are for specific things, so if you want anything else, you still have to get a job.