In both social science and medicine, research on reproduction generally focuses on women. In this article, we examine how men's reproductive contributions are understood. We develop an analytic framework that brings together Cynthia Daniels' conceptualization of reproductive masculinity (2006) with a staged view of reproduction, where the stages include the period before conception, conception, gestation, and birth. Drawing on data from two medical sites that are oriented to the period before pregnancy (preconception health care and sperm banks), we examine how gendered knowledge about reproduction produces different reproductive equations in different stages of the reproductive process. We conclude with a new research agenda that emerges from rethinking the role of men and masculinity in reproduction. © 2013 by The Author(s).