Ages at Reproductive Health Transitions in the United States

Lawrence B. Finer, Guttmacher Institute
Lindsay Dauphinee, Guttmacher Institute

Key reproductive events such as first intercourse typically mark different life stages with varying service needs. We use four National Surveys of Family Growth from 1982 to 2002 and event history techniques to calculate median ages at various events for women and men. We find that age at menarche has not declined, contrary to published reports. Women’s median age at first sex fell from the 1939 birth cohort through 1974, then increased slightly, to 17.6 for the 1985 birth cohort; median age for men was stable from 1960 to 1978, then increased to 17.7 for the 1985 cohort. Median age at first union (either marital or cohabiting) was stable for men and women, at about 22. Women’s age at first marriage increased but age at first birth plateaued; by 1999 (the 1974 birth cohort), median age at first birth was earlier than first marriage. This gap also narrowed for men.