"Why has this happened? There are two possible explanations to consider: money and culture.
Money readily comes to mind. If a welfare system pays unmarried mothers enough to have their own apartment, some women will prefer babies to husbands. When government subsidizes something, we get more of it. But for many years, American scholars discounted this possibility. Since the amount of welfare paid per mother had declined in inflation-adjusted terms, and since the amount paid in each state showed no correlation with each state’s illegitimacy rate, surely money could not have caused the increase in out-of-wedlock births.