"Since Mom and Dad were killed in an auto wreck, the three of us get to stay together only as long as we behave" (3).
Ponyboy's parents are dead at the beginning of the book, having passed on due to a previous accident. Now there are just three brothers living together without parents; but, the oldest brother Darry and Ponyboy don't get along very well, which drives Pony away from the house. Luckily, it isn't just the three boys against the world because they have friends who hang out at their house and fill in the different voids of a family. Where Darry isn't the consoling father-figure, Soda and Dally are. Where Pony doesn't have a little brother, Johnny fills in. Luckily, Pony also gives Johnny what he needs as a brother and a confidant. Everyone, along with Two-bit and Steve are protectors of each other where adult figures aren't or can't be. Hence, the boys fill in where adults or protection for each other aren't and they create a non-traditional family where most of everyone's needs are fulfilled. It isn't unheard-of for gang members to feel closer to each other than their own families because of the loyalty, respect, and love they find between them.
Here's one poignant quote that shows why kids are a part of gangs is after Ponyboy explains Johnny and how the gang defends him to the Socs and supports him: "If it hadn't been for the gang, Johnny would never have known what love and affection are" (12). Johnny never received any love from his parents at home, so the gang was the only place he felt that and that's why a gang can be considered a family for sure.