Yes, religion seems to be the only arguement against homosexaulity... however, when it is told to jump off a cliff in every discussion that takes away one more arguement from that person.
And, homosexuality is abnormal. For whatever reason, humans evolved/were created in two distinct genders, along with most other animals. One can infer that a being from one gender would, naturally, mate with the being from the other gender. However, why bother with genders at all if we're going to have men with men, and women with women. Why don't we reproduce asexually with an ability for that immense pleasure and emotion as common as a cold, and able to be turned on and off. That is one of my qualms.
(And I would like to apoligize in advance if someone who is reading this is a homosexual and is offended by what I am writing. I am not trying to offend, I am just stating my opinion.)