The review revealed that inmates with the 47/XYY chromosome type are more often tall than those with the normal type; usually free of other distinguishing physical characteristics; mentally immature; of normal or subnormal intelligence; aggressive and irresponsible with a lack of self-control; and lacking in emotional ties. They usually have underdeveloped or otherwise abnormal testicles, and they tend to commit either property or violent crimes. The two inmates described in the case studies were found in a group of ten tall inmates who volunteered to participate. (Two other inmates in the group were found to have chromosome mosaics which included the 47/XYY type.) The first was born in 1930 and had spent his childhood with his grandparents. Because of 'nervous agitation,' he had to repeat a year of elementary school. He received no job training and worked as a laborer in various capacities. At the age of 20 he committed his first offense--embezzlement. At the age of 27 he married a woman who was 10 years older, had a son, and later separated from his wife. He was convicted 27 times, usually for fraud, forgery, and practicing professions for which he was not qualified. His personality is unstable, and he forms only weak emotional ties. Although he knows when he has commited crimes, he cannot resist criminal impulses. An electrocephalogram examination revealed no unhealthy changes. The second inmate was born in 1947 and raised in an orderly family atmosphere. At the insistence of his parents, he joined the navy, where, at the age of 19, he killed a fellow sailor in a fight. He forms weak emotional ties, and his crime appears not to affect him. The electrocephalogram examination revealed no abnormalities. Chromosome diagrams, summary data tables, and a bibliography of 78 items are included. -- in German.