Having moved on from biblical interpretations, sexual preferences are usually considered absolutely forbidden if participants can't give informed adult consent. So - voyeurism, anything involving children and animals, and so on.
There doesn't seem to be much evidence that sexuality can be changed by conscious choice. So if your sexuality runs along those lines you're going to have a bad time, because you'll either have to repress your urges, or risk actions that damage others, possibly with criminal consequences.
The edge cases of this can become ridiculous - but still tragic. E.g. there are people who are primarily turned on by paving stones and/or drain covers.
It's not really obvious what "natural" means in this context. Is this imprinting? Genetics? Something else? There aren't any good answers. Criminal law does the best it can with them, but it's not clear that choice really applies, and criminal punishment is pointless and ineffective anyway - either as a deterrent or as rehabilitation.
The bigger moral question is maybe why some social groups seem obsessed with what they consider sexual deviance - including their beliefs about homosexuality - while apparently ignoring other moral and social questions.
What is the psychological process that turns homosexuality into a uniquely disturbing moral problem for them, while other hot-button issues - poverty, diet, government and corporate corruption, take your pick from a long list - are relatively uninteresting for them?