Why some women develop debilitating postpartum depression after childbirth and some women are spared has long been a curiosity. Researchers are homing in on two genes, which they suspect may be particularly reactive to estrogen, as a possible explanation for why depression afflicts some women more than others after childbirth. A small study that recently appeared in the journal Molecular Psychiatry hones in on two genes, which when altered slightly appear to exacerbate depression. These genes, the scientists involved in the study note, appear to be particularly sensitive to the hormone estrogen, which is elevated during pregnancy. While the work is preliminary, they suggested it could ultimately lead to screening that could alert women they are vulnerable to depression after childbirth.