the evolutionary roots of the base revisited...,

In the above CDC map, the key indicates the number of births for every 1,000 women between the ages of 15 and 19 in a state. For example, in dark green states, there are 50 or more pregnancies for every 1,000 women between the ages of 15 and 19.

TheAtlantic | In 2009, a landmark study found a strong correlation between religion and teen pregnancy. The CDC's newest data suggests not much has changed. Teen pregnancy closely follows the contours of America's Bible belt, according to the map (above) from the Centers for Disease Control (CDC).

There is good news: teen births are at their lowest level in more than 60 years (10 percent lower than 2009, 43 percent below their peak in 1970). But the geographic variation is substantial.

Teen birthrates are highest in Texas, Oklahoma, Mississippi, Arkansas, and New Mexico,. There are slightly lower concentrations in the neighboring states of Louisiana, Alabama, Georgia, South Carolina, Tennessee, Kentucky, West Virginia, and Arizona. New Hampshire, Vermont, Connecticut, and Massachusetts have the lowest rates of teen births.

What factors lie behind this geographic pattern?

With the steady statistical hand of my Martin Prosperity Institute colleague Charlotta Mellander, I took a quick look. Of course, the correlations we found are not the same thing as causation. Other factors we have not considered may come into play.

Teenage births remain high in more religious states. The correlation between teenage birthrates and the percentage of adults who say they are “very religious” is considerable (.69). The 2009 study posited that attitudes toward contraception play a significant role, noting that "religious communities in the U.S. are more successful in discouraging the use of contraception among their teenagers than they are in discouraging sexual intercourse itself."

Teen birthrates also hew closely to America’s political divide. They are substantially higher in conservative states that voted for McCain in 2008 (with a correlation of .65) and negatively correlated with states that voted for Obama (-.62).

Class plays a substantial role as well. Teen births are negatively associated with average state income (-.62), the share of the workforce in knowledge, professional, and creative class jobs (-.61), and especially with the share of adults who are college graduates (-.76). Conversely, teen birthrates are higher in more working class states (with a positive correlation of .58).

Overall, teen birthrates remain highest in America’s most religious, politically conservative and blue-collar states.