"There's this huge explosion in all three of these countries of the gangs and the number of gang members, partially because it's the way of street kids getting status and reputation, and partially because it's a way of surviving," said Tom Ward, a USC associate professor who has studied the issue. At least 80 percent of youths stopped at the border have one parent or a close relative already in the United States, said Doris Meissner, former commissioner of the U.S.