The “midlife crisis” was first successfully promoted in the United States with journalist Gail Sheehy’s Passages (1976) as a feminist idea, which described middle life as the point when men and women abandon traditional gender roles. Psychological experts responded with a male-centered definition of middle age, which banned women from reimagining their lives. Presented and received as more scientific, this became the dominant meaning of “midlife crisis.” This paper reverses histories of “popularization” by tracing how an idea moved from popular culture into academia. It examines the gender politics of scientific demarcation and shows that the midlife crisis has historical roots in debates about gender roles.