Some problems in maternal age.
D000130:Achondroplasia; D018376:Cardiovascular Abnormalities / Q000209:etiology*; D004314:Down Syndrome / Q000209:etiology*; D006801:Humans; D008423:Maternal Age; D009035:Mothers; D014427:Twins
ACHONDROPLASIA; CARDIOVASCULAR DEFECTS, CONGENITAL/etiology and pathogenesis; MATERNITY; MONGOLISM/etiology and pathogenesis; TWINS