title: Decline in coital rates with spouses' ages and duration of marriage.
mesh_terms: D000328:Adult; D000367:Age Factors; D003075:Coitus; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008393:Marriage; D013997:Time Factors; D014481:United States