A microscopic piece of genetic material known as the Y chromosome made headlines last week. It is nothing new or rare; every man has one in practically every cell, or he would not be a man. But a few men have two. Richard Speck is said to be one such; his attorneys are now preparing an appeal against his death sentence for the 1966 slaying of eight nurses in Chicago. Another is Daniel Hugon, awaiting trial in Paris on a charge of having murdered a prostitute. His lawyers contend that he is mentally unfit to stand trial because of his chromosomal abnormality, and the Paris court has appointed a panel of experts, including both a psychiatrist and one of the world's most brilliant geneticists, Dr. Jerome Lejeune, to advise it.
The theory that a genetic abnormality may predispose a man to antisocial behavior, including crimes of violence, is deceptively and attractively simple, but will be difficult to prove. The argument in its favor rests upon the fact that in a few prisons sampled in the U.S., Britain and Australia, the proportion of inmates with an extra Y chromosome has been found to be higher than in the general population. The objections to the theory are that no one knows the true incidence of the extra-Y abnormality, and that even when it is shown to exist, no one knows how the second Y can influence personality, let alone criminality.
Supermale? Nature intended every man and woman to have 46 chromo somes per cell: 22 pairs of autosomes, which determine countless characteristics other than sex, and two gonosomes or sex chromosomes. In the female, these are a pair of Xs; in the male, an X and a Y (see diagram). When a sperm fertilizes an ovum, each supplies half the 46 chromosomes for the combination of cells that will grow into a baby. If the sperm contains an X chromosome, the baby gets that X plus one from the mother, and will be an XX girl. If the sperm contains a Y chromosome, the baby gets that plus an X from the mother; the potent male Y overpowers the single X, and it's a boy —normally, XY.
But sometimes, when the first cells are dividing and both lines of chromosomes are supposed to make duplicates of themselves, nature slips up. Instead of splitting them into two neat rows of 23 each, it leaves an extra X or Y in one row. If the supernumerary is an X, the baby has an XXY pattern and will grow into a sterile, asthenic "male," usually with some breast enlargement and mental retardation—a condition that physicians call Klinefelter's syndrome.
This has been recognized since 1959. Despite the factor of low intelligence, it has not been linked with criminality. If the extra chromosome is a Y, the baby gets an XYY pattern and is unquestionably male. Or, as evidence gathered by an all-woman team of researchers in Scotland now suggests, he may be a supermale, overaggressive and potentially criminal. Dr. Patricia A. Jacobs and her colleagues working at Western General Hospital in Edinburgh knew that a number of mentally defective men with a double dose of both sex chromosomes, or XXYY, had been found in Swedish and English institutions as criminals or hard-to-manage inmates.* This made the researchers wonder whether it was the extra Y that predisposed the men to aggression. They decided to check on simpler, XYY cases, previously seldom reported.