Not only is it absurd to try to compare mammals to lower species (since no male mammal is capable of spontaneously producing ovaries and a uterus, nor is any female mammal capable of spontaneously producing testes), but human homosexuality runs completely counter to the basic premise of his argument: that sexuality is flexible in nature
"to solve the problem of how to survive and make as many babies as possible."When humans engage in homosexuality, they produce zero progeny and their average individual life spans decrease dramatically.