Two primary reasons for gang joining are prestige and protection. Prestige comes in two forms: negative prestige and positive prestige. Most often, youths join gangs out of negative prestige, which is fear based: they are frightened of the gangs so they subjugate themselves and join to feel safe. Positive prestige is dominance based: bullies join gangs to overpower other, weaker people. Protection is sought through gang-joining to provide safety from groups that are "others": not one's own ethnic, cultural, social, or economic group.
One thing we might consider in this discussion is the idea of "legacy." True, socio/economic reasons are a factor, as are a sense of identity. We cannot overlook, however, the idea of legacy with regard to gangs. If a young man is in a gang, then his brothers are expected to join the gang as well. If young men are unwilling to join the gang, they are often forced to join through fear and intimidation. One might ask, why they gangs force unwilling participants to join.
Young people, especially teenagers, often join gangs because they yearn for the respect that gang members often have within their social group. They see gangs as cool or sophisticated and want to be associated with those things. It is not uncommon for a teen to have a parent with a gang affiliation. I think kids get involved thinking they are going to have lots of money and popularity. Gangs, of course, have that element of danger that appeals to kids who like to take risks. Honestly, it is sometimes easier for kids to join gangs than to put up resistance.
I think we can link such reasons to a wider social malaise regarding the breakdown of families and the whole concept of belonging. As parents have to work more and more and many children grow up in one parent families, they are not able to receive the same care and love and attention as they need. Therefore they seek out this care, love and sense of belonging in gangs.
I suppose that different people join gangs for different reasons, or more accurately, for a combination of reasons. The typical profile for a gang member would be someone who needs the type of fraternity and support that gangs provide because they lack it elsewhere in their lives. Some others may join in order to rebel. Others may see it as the only way to achieve any sort of empowerment, or even wealth, in their surroundings. For others it is, perhaps, peer pressure.
It's part of the human makeup to want to be recognized and valued by someone. We all need to love and be loved; the challenge lies in finding ways to fulfill that basic need. For those who are unable to find emotional security in their family setting, other groups become the source of support. For all the reasons previously stated, gangs become a substitute family for some individuals, even when the relationship is twisted and based on manipulation, fear, or other negative emotions.
I think the combination of the first two posts covers quite a few reasons. But one of the other reasons that young people join gangs is not just to feel like they belong or to have some money in their pockets but also because they live in fear and the gangs offer a sense of protection. Their lives are filled with danger and the opportunity to get some relief from at least some of them is pretty appealing, especially when combined with all the reasons above.
I agree with the above points, but since most gangs engage in regular criminal activity, I believe financial gain is also a prime motive. I'm sure that many gang members come from families that are not totally dysfunctional, and that the lure of what seems to be easy money is a main attraction. Gang life also seems to exude an exciting and "macho" sort of glamor, undeservedly glorified in music and film, and this also serves as a means of attracting misguided youth to its ranks.
I believe that they join gangs because they need to feel like they belong and like they are significant. These are often youths from backgrounds that do not get much respect in our society -- poor people, immigrants, etc. Because of this, and because they feel like they don't have much chance to get ahead in our society, they feel like they aren't important. They may not have good families to give them a feeling of belonging. For these reasons, they join gangs, where they can feel like they belong and where they can feel like they are big shots, at least in their neighborhoods.