The teen on the left was a Latin King; the one on the right was his brother, a Harrison Gent. The young lady was their sister. The two gangs were friendly with each other in Uptown during the mid-1970s. It was not uncommon to see members hanging out together. They even had a joint mural on Winthrop.
In an unrelated vein, notice the stonework on the apartment building in the background. It conjures up images of a once proud neighborhood before urban decay, street gangs and poverty took their toll on these architectural gems.