Being gay was considered a mental illness up until 1973 when it was removed from the DSM-3. What changed? Well, nothing really except increased social tolerance for sexual deviance. Much of what gets classified as a mental health disorder is driven by shifts in collective societal perspectives.
Hey did you know the reason they took it out? It had nothing to do with a reasoned debate on the merits but due to violent protests that disrupted the American Psychological Associations (APA) annual meetings. Gay rights activists disrupted the APA convention in 1970-1973. The APA board of trustees voted to remove homosexuality from the DSM-III. It was taken out with a threat of force from activists and protesters. So the reason homosexuality isn't considered mental illness officially is the threat of violence, you will declare me sane or I will hurt you! A fist is not an argument, it is an expression of aggression, frustration, or dominance, whereas an argument is a verbal exchange of opposing views, opinions, or claims.
The debate surrounding the classification of homosexuality continues behind closed doors, with some psychiatrists arguing that the removal of homosexuality from the DSM was premature or misguided. For example, having one mental illness you are more likely to have another mental illness comorbidity with it. Now if you are homosexual, even if we don't consider that a mental illness, you are still more likely to have another mental illness comorbidity with your homosexuality. Just like we would expect if it were a mental illness. Another thing is does this mental condition cause you to lose a significant part of your life, well yes you don't reproduce and now are sterile, so I'd say under this rubric, it also qualifies as a mental illness, in that your illness, sterility, is caused by your mental condition. Research suggests that gay individuals, particularly men, tend to be more present-oriented in their daily lives and decision-making processes with a focus on immediate gratification and increased emphasis on hedonism with less emphasis on long-term planning than heterosexuals. Present oriented individuals tend to focus on the current moment and may struggle with anxiety or depression related to past traumas or future uncertainties. Some common present oriented mental illnesses include: Dissociation, Post Traumatic Stress Disorder and Borderline Personality Disorder. There is an increase in these disorders in gay people.
Now I'm not saying gays should be lobotomized or imprisoned. We can admit they have a mental illness and still treat them well. But perhaps we don't have to celebrate their lifestyle and can keep them away from children. It's like don't be rude to a guy in a wheelchair and that is fine but do we want encourage children to break their legs to grow up to be in a wheelchair?