Men in the U.S. kill many more individuals than women do. They are also far more likely to use a gun, whether the victim is an adult or a teenager. But they are more likely to use a weapon other than a gun when the victim is under age 13.
Female killers, however, are more likely to use a weapon other than a gun—a blunt object, knife or poison, for example—against all age groups. The reasons are unclear, but the differences between men and women are striking.
Numbers here are from FBI data on more than 13,000 killing incidents in the U.S. in 2010; they include murders, negligent manslaughters and acts of self-defense but not suicides.
For more on the types of weapons used by killers, see "People Kill with Guns More than Any Other Weapon" in the July issue of Scientific American.