A really proportion of homosexuals were abused as children. It seems to be the case that a person if caught at the right age and state of psychological vulnerability, can be essentially “turned gay”.
Rather than the brain being fluid, how many young boys, in early adolescence, when hormones are raging, are provided easy-to-get sexual experiences by older men. Many young boys are timid around girls. Some have first sexual contact with aggressive men, convince themselves they are homosexual and stay in that lifestyle, even though biologically they are not any kind of outlier on the male/female continuum. Normalizing homosexuality is not a positive.