Background: Childlessness is a major public health concern in the United States, particularly among educated adults. Among women who turned 45 in 2006, one fifth had no children. We examine the likelihood that a childless woman wants a baby sometime in the future and its determinants. Methods: From 2006 to 2010, 5,410 in-person interview surveys were conducted with childless women as part of the National Survey of Family Growth. Age-specific likelihoods of wanting a baby were compared with likelihoods of having a baby before age 45. Female respondents were 1) born after 1960, 2) age 15 to 44, 3) childless (never given birth to a live infant), and 4) not pregnant at time of interview. Findings: Most childless women at any age want a baby sometime in the future. By age 32, fewer than half the childless women who want a baby will have one. At age 39, the majority of childless women (73%) still want a baby someday, but only 7% will have one. By age 45, more than 1 in 10 women will be childless, but still want to have a baby. Conclusions: Although attitudes toward childlessness have become more positive over time, our findings suggest that the United States is experiencing a high prevalence of childless women who want a baby. Clinicians may consider counseling young women about age-related declines in fertility and the costs and success rates of assisted reproductive echnologies often required for women with advanced maternal age to better inform their career, family, and lifestyle decisions. © 2014 Jacobs Institute of Women's Health.