You should be aware that the statistics about smoking and homosexuality are rather similar. Research done prior to the advent of protease inhibitors (the antivirals that have extended the lives of people with HIV), showed that homosexual men live between 8 and 20 years less than normal on average. (The uncertainty was mainly due to an uncertainty as to what percent of the male population is homosexual.) But cigarettes reduce the lives of smokers by an average of fourteen years (see http://www.cdc.gov/tobacco/research_data/economics/mm5425_highlights.htm.)
You are correct that homosexuality has not been proven to be genetic. However, there is evidence that genetics plays a role. (Up to 50%, according to research involving identical twins.) But the truth is that no one knows the cause of homosexuality. Most likely environment and genetics both play a role. None of the usual theories seem to work very well at predicting sexuality. For example, some say that a distant father, or sexual abuse at the hands of a male, etc, cause homosexuality -- but the rub with such theories is that there are plenty of heterosexual men with similar unfortunate experiences.
Great! So we should promote smoking along with homosexuality in public schools. The dangers are roughly the same (depending on which study you want to bring up). We should have "Be tolerant of smokers days." "My Daddy smokes like a chimney and drinks like a fish (and it's cool) day." Kids write letters to congress telling them that chain smokers should be allowed to adopt, etc.
You are correct that homosexuality has not been proven to be genetic. However, there is evidence that genetics plays a role.
And the same can be said for crime. Should we promote crime due to this? The same logic is being applied in order to promote homosexuality. He/she can't help it - they were born that way."
"statements of position issued by the American Psychiatric Association, the American Medical Association, etc."
You are aware that these position statements didn't come about until these organizations were "infiltrated" by homosexuals. I know in the case of the Psychiatric association they bowed to pressure by homonsexuals to change the definition of homosexuality.