So often so many things are labelled "sinful" with the explanation that they are unnatural. The Bible frequently points out actions that should be avoided because they are unnatural. However, does something that is unnatural necessarily mean it is sinful?
As a result of the Fall, we are odds with the created world around us, which would mean plenty is unnatural due to this fact. We do not call of these situations sinful, though. Neither does the Bible.
Take the whole book of Job. Plenty of unnatural occurrences for this poor man which should be avoided if possible. Yet one of the clear messages was that he was not sinful.
What about the blind man who Jesus healed? Remember the debate about who sinned? Jesus said it was not because of sin. Blindness is unnatural. Yet it is not sinful. It is the result of the fallen, broken world, but would not be considered to be the man's fault.
We can continue this line of thought through a variety of medical conditions, from the common cold to cancer. In the mental health field, we often apply these ideas to de-stigmatize and normalize mental illness. While clearly abnormal, schizophrenia, bipolar, depression, anxiety, etc. are not sinful. Sometimes behavioral sin can lead to these conditions. In my professional experience, though, this is not the case. Being anxious is not a sin. Being depressed is not a sin. Being schizophrenic is not a sin.
So what about other things we call sins simply because they are unnatural. Is that a fair label? When is it accurate and when is it not?