title: Methodological issues in family, adoption, and twin research.
authors.affiliation: Francis Scott Key Medical Center, Baltimore, MD 21224.
authors.forename: D S
authors.initials: DS
authors.lastname: Svikis
authors.forename: R W
authors.initials: RW
authors.lastname: Pickens
mesh_terms: D000300:Adoption; D000375:Aging; D000437:Alcoholism / Q000150:complications; D004200:Diseases in Twins; D005190:Family; D005260:Female; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000150:complications; D012107:Research Design; D012737:Sex Factors; D019966:Substance-Related Disorders / Q000235:genetics; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic