Income inequality and teen pregnancy

Breathless reporting over the alleged damage wrought by income inequality continues apace over at The New York Times, with the paper's Economix blog highlighting a new paper linking inequality with teen pregnancy:

In general, teenage pregnancy is more common among poor girls. But poor girls who live in places with a high level of inequality — meaning that the ratio of income at the median of the income distribution to the income at the 10th percentile of the income distribution is higher than in other places — are even more likely to become pregnant as teenagers.

The new paper [by economists Melissa S. Kearney of the University of Maryland and Phillip B. Levine of Wellesley College] looks at inequality across states and finds a very similar correlation [emphasis mine] between the rate of teenage births and income inequality. For example, a teenage girl in Mississippi is four times more likely to give birth than a teenage girl in New Hampshire. The researchers conclude that teenagers in the highest-inequality states are roughly five percentage points more likely to give birth as teenagers than teenagers in the lowest-inequality states.

Inequality, the authors suggest, makes the poorest citizens believe that they have little chance of economic mobility. They are becoming pregnant “at a young age instead of investing in their own economic progress because they feel they have little chance of advancement,” the authors write.

One interpretation of that last paragraph (we are forced to rely on blogger Motoko Rich's comments on the paper as the actual study is behind a paywall) is that the authors claim young women are choosing motherhood over a more ambitious career/employment path because they see little benefit to it from an absolute perspective. While perhaps plausible, this has nothing to do with income inequality. Income stagnation and/or an ability to improve one's standard of living is a problem regardless of whether the gap between the rich and the rest is expanding. If Bill Gates and the Wall Street crowd had faced mediocre earnings growth over the past decade it would make a lack of economic advancement among the poor no less of a problem. 

The other interpretation is that teenage girls are choosing pregnancy over work ambitions because it will provide insufficient economic progress from a relative perspective; that advancement is pointless unless it places one at a higher relative standing. This is ludicrous. Does any person -- especially a poor teenager -- really consciously opt for motherhood over a career because, while the career may enable the individual to raise their absolute standard of living and afford new creature comforts, that their standard of living will not increase as rapidly as that of a hedge fund manager? Is this the sophisticated analysis teenagers engage in before getting pregnant? Such are the mental gymnastics one must perform in order for the teenage pregnancy-income inequality linkage to have a causal relationship.

Perhaps more mind-boggling is the blog post's final paragraph:

The authors do acknowledge that a change in inequality does not explain the drop in teenage childbirth in the United States over the last two decades. That, they say, is a topic for more study.

Suffice to say, rising income inequality corresponding with a drop in teenage pregnancy would seem to be a rather inconvenient fact when one is attempting to establish a causal linkage in the other direction. 

If income inequality is so obviously a societal threat, why are the facts in support of this thesis so difficult to establish? Why are the arguments so poor? Again, one is left with the distinct impression that inequality doom-mongers are simply throwing whatever arguments and facts they can at the wall in the hope that something, anything will stick.