Chromosome examinations in aged twins.
D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging; D000782:Aneuploidy; D005260:Female; D005838:Genotype; D006801:Humans; D007962:Leukocytes / Q000166:cytology; D008297:Male; D011123:Polyploidy; D011247:Pregnancy; D014427:Twins