I can't think of any good definition of "(un)natural" according to which it would be correct to say that homosexuality is unnatural. We should first recognize that defining "homosexuality" is itself a difficult task. I'll begin by distinguishing between being a homosexual person and homosexual acts, where the latter involves sexual activity between members of the same biological sex. An overly simplistic way of defining a homosexual person would be someone who identifies him or herself as wanting (when wanting to engage in sexual activity) primarily to engage in homosexual acts, but this definition neglects other important ways homosexuals think of themselves (e.g., as loving or wanting to marry someone of the same sex). Now, how could it be that homosexual acts or homosexual persons are unnatural? 1. Perhaps one thinks that *hetero*sexual acts (and persons) are natural and any other type of sexual activity is (thereby?) unnatural. But this view just begs the question of what counts as...

I think the logic is fine, but I'm not sure about the content of the argument. The argument structure is: 1. X is an institution with an essential goal that is clearly immoral. 2. It is wrong for individuals and institutions not to do what they can to prevent an institution from achieving immoral goals. 3. So, it is wrong for individuals and institutions not to do what they can to prevent X from achieving its immoral goals. If we fill in Nazism for X and wiping out Jews for their essential immoral goal, the valid argument also looks sound (i.e., the premises and therefore the conclusion are true). But if we fill in Christianity for X, that argument is less clearly sound, mainly because Christianity is a much more diverse institution than Nazism with more varied essential goals. Some Christians take their religion to require fighting against homophobic practices, just as some fought against slavery and racism, while other Christians take it as an essential implication...

The statistical norm might be defined by what is true of the majority. But why on earth would we want to define the moral norm solely in terms of what the majority of people do? That would mean that, by definition, vegetarianism, atheism, and marriage between different races was wrong. It would mean that you were morally wrong if you were an abolitionist in the South or fought for equality for women in America in the early 20th century (I'm not sure when that became the majority position) or fight for equality for women in many countries today. For that matter, it would make it wrong to be a Jew or a man who goes to college or a firefighter. Perhaps what you mean is that homosexuality could be considered biologically "non-normal" (it's not clear exactly what that might mean, since whatever we do is allowed by our biology). That may not be true, depending on what one means by biologically normal. But even if it were, it would not make it morally wrong, since lots of biologically "non...

Yes, especially if it involves the actual infliction of pain on someone else, not just getting pleasure from watching real or fake depictions of people in pain. On every theory of morality, gratuitous or unnecessary pain is wrong and should be avoided. Some theories try to ground that moral claim in more fundamental moral claims, while others, such as utilitarianism, treat "pain is bad" as a fundamental fact from which to derive moral conclusions. If you believe there are no moral truths, then sadism is not immoral because nothing is, but in that case, there's nothing special about sadism except that, like rape or murder, it is a particularly counterintuitive case for people who think there are no moral truths. A more interesting question is whether masochism is immoral (i.e., deriving pleasure from the experience of pain, though this definition itself is philosophically perplexing if one defines pain and pleasure as opposites!). Or what to think about a sadist and a masochist getting together...

There's a lot of subtext in your question--you seem to be suggesting that if there are genes that influence whether one is homosexual or heterosexual, that indicates that being gay is a mental illness. That would be a very strange argument, since the fact that there are genes that influence traits or behaviors says nothing about whether that trait or behavior is good or bad in either the biological or ethical sense. Perhaps you are thinking that because homosexuals do not have the desire to mate with the opposite sex, any genes that may underlie homosexuality are "maladaptive" in the way some mental illnesses are caused by maladaptive genes. But that is also a mistake, since (a) in humans' past evolutionary environments homosexuals may have reproduced (they wouldn't be the only humans who have had sex for procreation without being particularly attracted to their mates!), (b) there are interesting data suggesting that homosexuality in some animal species (perhaps including humans and their...