A study published in BMC Public Health found "a spike in miscarriages of baby boys throughout the U.S. in September 2001. Researchers blame the stress moms-to-be suffered because of 9/11 - even if they had no direct link to the terrorist attacks." Miscarriages were up 12% the normal number for September, and the study's writers attribute it to "communal bereavement." Lead writer UC Irvine professor Tim Bruckner said, "We do grieve for people we don't know." Additionally, male fetuses were more affected because "they are more sensitive to the chemicals mothers produce when stressed." Here's an abstract of the study.