Some common arguments for the conclusion that homosexuality is wrong (this might mean that certain behaviors are wrong, or that certain attitudes and feelings are wrong to have, or certain relationships are wrong, and/or other more precise conclusions also). In all cases the premises clearly lead to the conclusion since the unstated premises are made explicit (in italics).
Are these arguments sound, or do they have at least one false premise?
1. Homosexuality is ‘different.’ [different from what?]
2. Anything “different” is morally wrong / If something is “different,” then it’s wrong.
3. Therefore, homosexuality is wrong.
4. Homosexuality’ is “weird.” [?]
5. Anything “weird” is morally wrong / If something is “weird,” then it’s wrong.
6. Therefore, homosexuality is wrong.
7. Society disapproves of homosexuality. [everyone? Someone? Which society?]
8. Anything society disapproves of is morally wrong / If society disapproves of something, then it’s wrong.
9. Therefore, homosexuality is wrong.
10. “Homosexuality is illegal.” [where?]
11. Anything that is illegal is wrong / If something is illegal, then it’s wrong.
12. Therefore, homosexuality is wrong.
13. My parents say homosexuality is wrong. [depends on your parents?]
14. Anything my parents say to be true is true / Anything my parents say is wrong is wrong / If my parents say something is wrong, then it’s wrong.
15. Therefore, homosexuality is wrong.
16. Homosexuality spreads AIDS and other STD’s. [it can (but this can be prevented, or one can try to prevent this?); heterosexuality activity can spread disease also, but people can try to prevent this).
17. Any behavior that spreads disease (or might spread disease) is wrong / If something spreads disease (or might spread disease), then it’s wrong.
18. Therefore, homosexuality is wrong.
19. Some people feel that homosexuality is disgusting and perverted; it makes them uncomfortable. [for some, true; for others, however, some, or all, heterosexual activities might make them feel that way.
20. Anything that makes someone uncomfortable or disgusted is wrong / If something makes someone uncomfortable or disgusted, then it’s wrong.
21. Therefore, homosexuality is wrong.
22. Homosexuality may cause “confusion” for children directly affected by a homosexual relationship.
23. Anything that causes “confusion” for children is wrong/ If something may cause confusion in children, then it’s wrong.
24. Therefore, homosexuality (or, homosexual relationships where children are involved) is wrong.
25. Homosexuality is a “non-traditional lifestyle.”
26. Any “non-traditional lifestyle” is wrong.
27. Therefore, homosexuality is wrong.
28. Homosexual sex has no potential for reproduction.
29. Any action that has no potential for reproduction is wrong / Any sexual action that has no potential for reproduction is wrong.
30. Therefore, homosexuality is wrong.
Not sure what the “argument” is here:
31. Homosexuality is a choice, and a wrong choice to make. (If it is not a “choice,” then it is not a wrong choice. If it is a choice, then we’ll want to hear why it’s wrong.)
32. Some people believe that homosexuality is a mental illness.
Arguments from the Bible:
33. “The Bible says homosexuality is wrong; religious views say it’s wrong.”
34. Anything the Bible says to be wrong is wrong. If the Bible says something is wrong, then it is wrong.
35. Therefore, homosexuality is wrong.
Arguments from what’s “natural”:
36. Homosexuality is “unnatural” or “not natural.”
37. If something is “unnatural” or “not natural,” then it’s wrong.
38. Therefore, homosexuality is wrong.
39. Homosexuality is “unnatural” or “not natural.” meaning __________________.
40. If something is “unnatural or “not natural” meaning __________________, then it’s wrong.
41. Therefore, homosexuality is wrong.
Arguments from the function(s) of the human body:
42. Homosexuality “goes against” natural human anatomy; our body parts weren’t designed for those purposes or functions; homosexuality violates our anatomy’s function.
43. If something “goes against” natural human anatomy, or if a body part is used for a purpose it wasn’t designed for, or it something violates our anatomy’s function, then it’s wrong.
44. Therefore, homosexuality is wrong.
45. Homosexuality threatens “family values” or “the family.”
46. Anything that threatens “family values” or “the family” is wrong.
47. Therefore, homosexuality is wrong.
 Mohr notes that not many other actions are called “unnatural” anymore. (p. 136).
A Dialogue on a more abstract arguments about homosexuality
C: I think homosexual activity is morally impermissible.
J: Why do you think that?
C: Because it does not lead to reproduction; it is using body parts for purposes they aren't supposed to be used for.
J: Hmm. First, I wonder how you can determine which purposes body parts should and should not be used for. But, setting that aside, lots of things heterosexual couples, even married ones, do does not lead to reproduction. Do you think those things are wrong?
C: Not necessarily. Since doing these things could lead to reproduction, or be part of a sequence of actions that could lead to reproduction, they can be OK, morally.
J: OK, so you think homosexuality is wrong not because it does not lead to reproduction, but because it could not?
J: What would you think about these cases then? There are woman without uteruses who can't get pregnant, and there are other women who - because of age or disease or lots of other causes -- cannot get pregnant. Do you think it would be wrong for them to have sex, since they cannot get pregnant, it's physically impossible for them?
C: Hmm, that's a tough question: I see how what I said seems to imply that. Let me see if I can come up with a better statement of my idea. I don't want to say that it would always be wrong for women who cannot become pregnant to have sex. But I do want to say that homosexuality is wrong. So what can I say to try to explain why, even though they are both non-reprodutive, one is wrong but the other isn't? How about this idea?
A sexual act is morally permissible only if, were it done by people able to reproduce, it would or might lead to reproduction or be part of a sequence of events leading to reproduction.
J: This is an interesting principle. If it's true, then, I guess, homosexuality would be wrong, but it wouldn't be wrong for these women above to have sex.
It seems to me, however, that this principle is, well, a bit complex. I don't see why someone should think it's true. Are there reasons that can be given for such a principle? Also, it almost seems to me that this principle is "tailor made" just for this conclusion: if the question is, "Why is non-reproductive, homosexual sex wrong?" your answer seems to be, "Because it's a non-reproductive sexual act done by people who cannot reproduce." To me, that doesn't seem to be a very informative answer.
C: Let me try to explain why you should think a principle like this is true . . .