Some observations concerning the decline of dizygotic twinning rate in France between 1901 and 1968.
D000293:Adolescent; D000328:Adult; D001723:Birth Rate; D003710:Demography; D005060:Europe; D005260:Female; D005602:France; D006801:Humans; D008423:Maternal Age; D010298:Parity; D011247:Pregnancy; D011272:Pregnancy, Multiple; D014427:Twins; D014429:Twins, Dizygotic