Kelly, I work in rentals in Calif. I routinely turn down too many unrelated folks for rentals. It is against the law here to discriminate against families. But, not against unrelated adults and adult siblings. Applicants say, "But, you're discriminating. if we were a related family you'd rent to us." I reply, "Yes, I am. Because I can!"
It's funny when I'm renting a 1 bedroom with a 2 person limit and they say things like, "But my girlfriend and I will be in one bedroom and our roommate will sleep in the living room." Like I care where they sleep!