Twins--still our best method.
D000300:Adoption; D002668:Child Rearing; D004200:Diseases in Twins; D005190:Family; D005219:Father-Child Relations; D005260:Female; D006801:Humans; D008297:Male; D010551:Personality; D011247:Pregnancy; D012107:Research Design; D012559:Schizophrenia / Q000209:etiology / Q000235:genetics*; D012931:Social Environment; D012934:Social Isolation; D013315:Stress, Psychological; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic