Why is a conversation about British youths who are from poor and disadvantaged backgrounds relevant?
Most kids these days are from poor and disadvantaged backgrounds. Certainly the vast majority are. The study in this instance (the organization has been around doing all manner of youth outreach since the 1970s) was about the negative effects of children who are deprived of their gender as an adult role model.
That includes 50% of all children caught up on gay lifestyles. Whereas with even single mothers (or fathers/daughters), they at least are still reaching out to the opposite gender "as mattering" when they date the opposite gender. In a gay home, that "mattering" has been completely shattered. In fact, that unhappy 50% child lives in a constant stew of their own gender as "institutionally not-mattering"....and that would send the most powerful psychological message of all.