Down's syndrome in families referred for advice.
D000293:Adolescent; D000328:Adult; D002869:Chromosome Aberrations; D003582:Cytogenetics; D004314:Down Syndrome / Q000235:genetics*; D005053:Eugenics; D005260:Female; D006801:Humans; D007621:Karyotyping; D008297:Male; D008423:Maternal Age; D008875:Middle Aged; D009030:Mosaicism