While reproductive health is a concern for all men of all ages, the earliest part of the life course—adolescence and early adulthood—is of utmost importance. Promoting the sexual and reproductive health of young men is a keystone to enhancing their health overall, to reducing some of the major health risks they face, and to establishing habits that will protect them throughout their lives. Promoting sexual and reproductive health for young men, a population that has been largely ignored, can lead to new inroads in promoting healthier lifestyles, preventing disease transmission, and reducing the unplanned pregnancies and births that are implicated in poor outcomes for children.