title: The first-born child: toddlers' problems.
mesh_terms: D001722:Birth Order; D002653:Child Behavior Disorders / Q000523:psychology*; D005193:Family Planning Services; D005260:Female; D005500:Follow-Up Studies; D006262:Health; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009043:Motor Activity; D011247:Pregnancy; D012890:Sleep; D012907:Smoking / Q000150:complications; D012923:Social Class; D014078:Tooth Eruption