Boiled down , there appears there might be an inheritable factor / trait that increases the chances of of acquiring homosexual tendencies- but does not guarantee it. So they can theorize that ]in some cases there could conceivably be genetic factors that alter the odds of acquiring sexual dysphoric orientation , Ego-dystonic sexual orientation and related psychosis that equate to being Gay. .
That - in of itself does not prove that anyone is born gay - it simply proves that some people have a greater chance of becoming Gay. due to environmental factors , enhanced by genetic defect.
Sexual preference is not a psychosis.
You are not qualified to make that statement . I give you the benefit of acknowledging that you are indeed an intelligent person - but you seem to have a problem distinguishing fact from theory and realty from fantasy - I believe we had that discussion in the past - and you were wholly incapable of telling the difference between a fact and a theory.
Psychosis is defined as "A mental state caused by psychiatric or organic illness, characterized by a loss of contact with reality and an inability to think rationally. A psychotic person often behaves inappropriately and is incapable of normal social functioning."
Many people within the gay community suffer from psychosis HOWEVER , many professioials , even unbiased ones will sometimes argue that homosexuality is not a psychosis as homosexuals and lesbians are able to think rationally, are
generally in contact with reality and are also usually able to function socially in a way people would see as normal.
So as to whether Homosexuality is a psychosis or not - is an opinion and not a fact - but it's an opinion and judgement that you are not competent to judge.