Ahrenfeldt LJ, Möller S, Wensink MJ, et al. - Researchers undertook this prospective cohort study to investigate whether fecundity, measured as self-reported time to first pregnancy (TTP), represents a marker for subsequent health and survival. Participants included 7,825 females and 6,279 males, aged 18 and above with measures on first TTP, who took part in one of the Danish nation-wide twin surveys in 1994 (twins born 1953–1976) and 1998 (twins born 1931–1952). They were observed from the interview until 2018, for mortality and hospital admissions. Findings revealed that long TTP behaved as a marker for elevated mortality in females as well as higher hospitalization rates for both females and males.