Unexplainable demographic phenomena of multiple births in Hungary.
D001723:Birth Rate; D003710:Demography; D005260:Female; D006801:Humans; D006814:Hungary; D007231:Infant, Newborn; D008297:Male; D008423:Maternal Age; D011247:Pregnancy; D012621:Seasons; D012744:Sex Ratio; D014310:Triplets; D014427:Twins