Over the long run unmarried fertility is positively associated with murder and property crime.
Wow.
This is the finding in the paper by Todd Kendall and Robert Tamura entitled, "Unmarried Fertility, Crime, and Social Stigma." I'd like to think that it should be more than due to the single parenthood situation, and that it may also have to do with the neighborhood and peers surrounding the child. Kendall and Tamura's theory goes like, "[c]hildren born to unmarried parents may receive lower human capital investments, leading to higher levels of criminal activity as adults. Therefore, unmarried fertility may be positively associated with future crime."
Futhermore, their paper has a particularling interesting application to developing countries (particularly countries with the majority of the population being religious), where single parenthood is not that common and where there is somewhat a social stigma attached to it:
"[I]n an environment in which social stigma attached to nonmarital fertility is high, many low‐match‐quality parents will marry, and children reared in these families may actually be worse off than if their parents had not married."
It does make sense. The pressure from the social stigma may force an unmarried parent to choose a partner in haste, who may turn out to be an imperfect partner. In addition, imagine what it will do to the child. Being brought up in a society where a complete family is everything, when all of a sudden you're introduced to a new father or mother without going through a slow but effective transition introducing the child to the parent. What a shock it would be for the child. Imagine what that will do to a child's core of values.
In an age where women empowerment is a trend--and single parenthood seems okay--this paper is saying that might not actually be the case. On the bright side, though, this is one good promotional material for dating websites.