I've got this conjecture that homosexuality is the result of a genetic modification for a beneficial survival trait, such as same sex bonding behavior leading to improved social cooperation, likewise causing a change to another trait, such as non-heterosexual preferences. It's not unknown for genetic modifications to cause multiple changes (for example, sickle cell anemia), and as long as the change provides a net benefit to the group then the trait is passed along. To me then, it's just part of nature. I suspect though that genetic engineering capabilities will eventually extinguish homosexuality, which may lead to greater social discord.