Why Do Single Moms Have Children in January?

New research* has found that women who give birth in different parts of the year tend to have different characteristics. The figure below displays this seasonal variation over the last 45 years.

Percent black mothers Percent white mothers Percent teen mothers Percent unmarried mothers

*Buckles, K. S. and Hungerman, D. M. (2013). Season of Birth and Later Outcomes: Old Questions, New Answers. Review of Economics and Statistics, 95(3):711–724.

Source: National Bureau of Economic Research, Centers for Disease Control and Prevention.