Twinning rates by residence in Denmark 1978 to 1982.
It has been suggested in the literature that twinning rates are reduced by psychosocial stress associated with urban life. No support for this hypothesis was found in a study based upon the 5,762 twins and 280,158 singletons that were born in Denmark in the period 1978 to 1982.
D000328:Adult; D003430:Cross-Sectional Studies; D003718:Denmark; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D011272:Pregnancy, Multiple; D012424:Rural Population; D014427:Twins; D014505:Urban Population