Murders within a family account for 16% of all big-city homicides, with wives the most frequent victims, according to a Justice Department study released Sunday.
Most of the assailants in family murders have been males, but the study--the first to focus on family relationships in murders--found contrasting statistics in all-white and all-black marriages.
Among white victims murdered by their spouse, 62% were wives and 38% were husbands. Among black marital partners, 53% were wives and 47% were husbands, meaning black wives killed their husband at nearly the same rate as husbands killed their wife.
For other racial groups, samplings were too small to reach conclusions, according to the study.
Parents killing their children was the second most frequent type of family murder, accounting for 21% of all homicides within a family.
Patrick Langan, one of the study's researchers, said black husbands and wives killing each other at virtually the same rate was one of several unexpected findings. Langan said he also did not expect to discover that parents killed their children as often as they do.
"I would have thought that such a bizarre event would have been the least frequent type of murder," he said.
The report, which did not assess reasons for any trend, was compiled by the Justice Department's Bureau of Justice Statistics from an unprecedented examination of more than 8,000 homicides in 75 large urban counties. The cases were taken from 1988, the most recent year for which dispositions were available.
Lawrence A. Greenfeld, who directed the study, said alcohol was a significant factor in many of the homicides.
"Sixty-eight percent of non-family defendants and 48% of family murder defendants were drinking at about the time of the murder," he said.
Among victims, about half of the non-family murder victims and a third of all family members who were murdered had consumed alcohol before the crime, the study found.
"Victims in spouse murders were the most likely to have been drinking--nearly 50%," Greenfeld said.
Authorities called the alcohol factor significant, even for the victims of homicide, because one-fifth of all cases studied showed the assailant had been provoked by the victim, either by a violent argument or by the brandishing of a weapon.
John Stern, deputy director of the National Organization for Victim Assistance, a nonprofit group, said the figures were shocking because "homicide is a preventable crime, especially among people who know each other."
Spousal homicide statistics would be even more dramatic "if we included former spouses who have killed one another in the years after their divorce," he said. A breakdown of such statistics was not available.
Stern recommended that high schools place more emphasis on teaching nonviolent conflict resolution, a subject he said is becoming popular even among prison inmates who are signing up in large numbers for the training.
"These courses are teaching tough young teen-agers about their capacity for empathy," he said. "We can reduce a lot of violence between people who know each other, not just between husbands and wives."
Excluding family members, nearly two-thirds of the remaining homicides were committed by friends or acquaintances of the victim, the Justice Department study showed. About 20% of the murders involved victims being killed by strangers.
Despite the notoriety of a case like the Menendez brothers in Los Angeles, who have been accused of murdering their parents, the report says children are killed by their parents at twice the rate that offspring kill their parents. But sons more often than daughters were defendants when their parents were murdered--82% versus 18% for daughters.
On the other hand, the murder of children was the only homicide category in which females predominated as killers, the study showed. In offspring murders, mothers accounted for 55% of all defendants.
Five Southern California counties--Los Angeles, Orange, Kern, San Diego and Riverside--were included in the department's study, but no county-by-county breakdown was made, officials said.