['The purpose of this study was to test the hypothesis that paternal race influences the risk for preterm birth.', "We conducted a population-based cohort study to examine the association of paternal race with preterm birth using the Missouri Department of Health's birth registry from 1989-1997. Birth outcomes were analyzed in 4 categories: white mother/white father, white mother/black father, black mother/white father, and black mother/ black father.", 'We evaluated 527,845 birth records. The risk of preterm birth at <35 weeks of gestation increased when either parent was black (white mother/black father: adjusted odds ratio, 1.28 [95% CI, 1.13, 1.46], black mother/white father: adjusted odds ratio, 2.10 [95% CI, 1.68, 2.62], and black mother/black father: adjusted odds ratio, 2.28 [95% CI, 2.18, 2.39]) and was even higher for extreme preterm birth (<28 weeks of gestation) in pregnancies with a nonwhite parent.'] Is paternal race a risk factor for preterm birth?