Even if one argues that the sin of Sodom is homosexuality then it would be more proper to say homosexual "rape" and not homosexual "sex". Lot offers his virgin daughter to satisfy the mobs sexual demand (which the biblical text supports in this story). The mob refues consensual sex and instead wanted rape.
Even if one find evidence against homosexuality in the Old Testament; a negative disposition toward homosexuality is not deserved. Much of the Old Testament laws are not observed due to changes in knowledge, morality and technological advances. If one defends his disposition of anti-homosexual stance from Scripture then to be consistent one must keep all the law, such as;
-Those who take the name of God in vain are to be put to death. (lev. 24:16)
-Creditors "at the end of every seven years....shall grant release." (Deut. 15:1)
-Do not eat rabbit and ham, bacon, pork chops, ribs and other pork products (lev. 11: 6-7 and Deut. 14: 7-8).
-It is an abomination to trim the hair on one's temple or to trim one's beard (lev. 19: 28)
However if one refuses to interpret the bible "literally"; then the above answer of "it is in the Bible" does not shed light on the truth of the matter (which is homosexuality). In order to interpret the Bible one must keep in mind the following quote "the spirit gives life but the letter kills" (Bible). The Spirit is to refuse prejudice born of ignorance that hurts people whose only fault is being born with a predisposition to the same gender. The letter is hate and the end of hate is murder and the end of murder is eternal pain.
According to some the biblical story of Sodom and Gomorrah is evidence that the Old Testament condemns homosexuality. However the real sin was inhopitality. In today's world the sin of inhopitality is not a major issue. However in previous centuries travelers depended on the hospitality of strangers for their very existence. The Sodomites wanted to humiliate the male travelers by forcing them to take the submissive role (of a woman) in sex. In ancient time this was the method of insulting defeated soldies and spies; whom these visitors were likely mistaken for. Here it is not a matter of homosexual sex but of using sex to debase the strangers. Please note that here the word "to known" in the biblical text is translated into sex. However some argue that the word "to know" used in the story of Sodom does not mean sex; as in the Old Testament out of the 943 times it was used only 10 refer to it as sexual.
Further proof that the sin of Sodom was inhospitality and not homosexuality is found in references to Sodom in the Bible. The following passage from the prophet Exekiel is quiet clear on the topic; (Ezekiel 16: 44-52)
