Buckles Kasey S, Hungerman Daniel M
University of Notre Dame.
Rev Econ Stat. 2013 Jul 1;95(3):711-724. doi: 10.1162/REST_a_00314.
Season of birth is associated with later outcomes; what drives this association remains unclear. We consider a new explanation: variation in maternal characteristics. We document large changes in maternal characteristics for births throughout the year; winter births are disproportionally realized by teenagers and the unmarried. Family background controls explain nearly half of season-of-birth's relation to adult outcomes. Seasonality in maternal characteristics is driven by women trying to conceive; we find no seasonality among unwanted births. Prior seasonality-in-fertility research focuses on conditions at conception; here expected conditions at birth drive variation in maternal characteristics while conditions at conception are unimportant.
出生季节与后期结果相关;但驱动这种关联的因素仍不明确。我们考虑一种新的解释:母亲特征的变化。我们记录了全年分娩时母亲特征的巨大变化;冬季分娩中青少年和未婚者的比例过高。家庭背景控制因素解释了出生季节与成人结果之间近一半的关系。母亲特征的季节性是由女性尝试受孕所驱动的;我们发现在意外怀孕分娩中不存在季节性。先前关于生育季节性的研究集中在受孕时的状况;而在此处,预期的出生时状况驱动了母亲特征的变化,而受孕时的状况并不重要。