There are no compelling secular arguments against homosexuality

My opponent has responded to my argument with 2 rebuttals.The first is a statement:"Homosexual behaviour is displayed in animals."The second is a rhetorical question "Is sex for procreation?"RR1) My opponent provides a report that shows that homosexuality happens in nature in various ways. However, what my opponent does ot answer is if this is a benefit or a dentriment to the reproductive fitness of the animal. In the case of the gay penguins, we see this happening in non-naturalsettings. My opponent also supplies a wikipedia article that gives several examples of gay animals in nature. However, in the majority of natural circumstances the so-called gay animals seek out females to mate with to produce offspring. Their reproductive urges override any other urges the animals may exhibit.The unequivicol fact is that an animal who does not mate with a member of the opposite gender cannot pass their genes into the next generation. Their exclusively homosexual behavior therefore is a dentriment to their repoductive fitness and from an evolutionary perspective is a"bad" (not that I did not say evil, as my opponent substitutes for me) decision. I would ask my opponent to show me any sexually reproducing animal in nature that is able to pass its genetic likness into the next generation without a member of the opposite gender to reproduce with. While the gay penguins may have fostered an egg provided to them, they did not pass their genetic information into the next generation. These gay penguins have reduced their own reproductive fitness to zero.RR2) My opponent seeks to misdirect this question to make this about the rightness or wrongness of homosexuality. He seeks to point out that reproduction is not the only purpose of sex. This is true! However, he resolution of the debate is not "there is no compelling exhaustive argument against homosexuality." Therefore, as Con all I must do is show that there is a perspective in which there is a compelling argument against homosexuality. I have done this. From the perspective of evolutionary science, which values the passing of ones genetic likeness into the next generation, homosexuality is counter-productive. From this perspective, a non-sterile partner should leave their sterile partner and reproudce with someone who is able (if both parties are sterile then their sexual choice makes no detraction from reproductive fitness in either the species or in these individuals). the same goes for elderly men leaving elderly women and mating with younger fertile women. There is nothing wrong with having sex without reproduction, however refusing to have sex without reproduction (as homosexuals are apt to do) is non-virtuous (virtue in its original meaning of "effective" or "efficient") and therefore is "bad" in an exclusively evolutionary minded view.Note, this is not my personal perspective. However, my personal perspective and the validity of it is not what we are debating. We are debating if a compelling secular argument exists against homosexuality. I have presented a perspective (evolutionary science) that holds an entierly secular perspective that considers homosexuality (in so much as homosexual mating is non-reproductive) as a negative effect.