Groups of adolescents, usually male, from urban working class or underprivileged districts, take part in aggressive and delinquent activities both within the gang and outside it, fighting other gangs, committing assault and theft and damage to property.
Since the late 1980s the number of adolescent girls – "gang babes" – involved in gangs has risen dramatically. They have proven to be as violent as, if not more violent than, their male counterparts, and show less remorse for the consequences of their violence.
Rarely are such gangs organized crime units, more often they are delinquent as a means for obtaining 'kicks'. Increasingly street gangs are involved in drug trafficking, intimidation and violence. Some gangs have initiation rituals, including shooting people.
Not all gangs are as well-organized and hierarchical as the Crips and Bloods in Los Angeles, but most offer a social haven for outcasts who crave a sense of belonging. Gangs are closely related to socioeconomic status, unemployment and a generalized feeling of disenfranchisement.
Youth gangs have developed in many countries, increasing (like the general level of juvenile delinquency) in countries with a higher economic level or with rapid social and economic change. In 1988, 622 wilding robberies were referred to New York City's family court. It is the second most common crime among youths in New York City, after crack dealing. In Los Angeles in 1990 there were some 750 gangs; in 1994 the estimate was 885 (570 Latino and 315 black). One of the biggest claim to have 10,000 members. By the year 2000 it is estimated that there will be 250,000 gang members in Los Angeles County. Gang-related robberies in 1989 were put at 1,800; murder at 570, and 800 or more in 1992.