There’s just one tiny problem with the whole single-motherhood-means-higher-crime-rates argument: if you look at the history of the past twenty years or so you will find that while single motherhood has been on the increase, violent crime rates have been going down, down, down.I can’t think of a single person that has ever asserted that single motherhood leads to higher crime rates. The closest I can get is that some have asserted that single motherhood leads to crime, albeit indirectly. The question, then, is not whether general violent crime rates are going up in correlation with single motherhood, but whether the children of single mothers commit a disproportionate share of violent crime.
The Heritage Foundation (quelle surprise) suggests in this dated post that there is a definite link between single motherhood and violent crime, but does not conclusively prove so, and fails to cite any sources for it. There is a general link between single-motherhood and self-destructive behavior, and apparently a link between being the offspring of a single mother and increased levels of aggression, but this does not conclusively prove that being born to a single mother makes you more likely to be a violent criminal.
On the other hand, none of the research disproves the assertion of a link between single motherhood and crime. In fact, it often suggests it. At any rate, once you focus on the actual assertion made by some conservatives instead of a straw man, you should find that the link between single motherhood and crime less immaterial than you might think.