HOUSTON -

The weeks before students head back to school can be filled with anxiety and uncertainty, but there's one serious problem that most families don't have on their radar, and that's gangs.

The Houston Police Department estimates there are more than 17,000 gang members affiliated with 200 documented gangs in Houston.

However, the threat is not limited to the city. The federal government's National Gang Center noted in 2009 that 55 percent of gang members were in big cities. More than 23 percent were in the suburbs and 18 percent were in small cities.

Those who work to fight the gang trend said the numbers are high because of ongoing recruitment. Patricia Harrington of the Mayor's Anti-Gang Office said gang recruitment is not specific to just one school district and often tough kids aren't always the ones targeted. Sometimes it's teens and preteen who get bullied.

"A lot of times gangs will say, 'We can be a protector of you'," said Harrington. "I would say the most vulnerable age are middle school ages, grades sixth through eighth."

Gang life can be attractive to some teens looking for a way to be a part of something and to stand out.

"They're looking for leadership, that guidance, and a sense of belonging," said Bradford Roland of the HPD Gang Division.

HPD sends officers to high-risk Houston Independent School Districts campuses to teach middle school students about gang resistance. The program is called G.R.E.A.T., which stands for Gang Resistance Education and Training.

"We see these kids doing well and then all of the sudden we see a drop in their grades and a change in their behavior," said Roland.

KPRC Local 2 got to ride along with Harris County Precinct 6 Constable Sgt. Julio Banda, who showed how gangs are a threat to vulnerable teens after school as well.

"A lot of times they go to parks to play basketball, and, believe it or not, the parks are one of the major recruiting areas for gangs," said Banda.

Gang life becomes a job as members are expected to earn for their crews. A lot of that responsibility falls on new, young, naive members who are suddenly caught up in something that's rarely as glamorous as what they see on television.