you could have saved yourself a lot of trouble by just saying you are bigoted rather than trying to pass off some sort of faux-rationality.
In the years since LBGT has entered mainstream discussion, at least since the 1980s(aids epidemic), the world population has steadily grown, and that is attributable to improvements in the availability of medicines, nutrition, and infrastructure. So I don't think you need to worry about the human race suddenly being ended by LBGT people, even a lot of them.
http://upload.wikimedia.org/wikipedia/commons/1/11/World_population_history.svg