title: Secular trends in menarche.
authors.forename: Frank M
authors.initials: FM
authors.lastname: Biro
mesh_terms: D017677:Age Distribution; D015992:Body Mass Index; D002648:Child; D005260:Female; D006801:Humans; D008572:Menarche / Q000208:ethnology / Q000502:physiology*; D014481:United States