I honestly don't know another example and way to describe it other than above. Like your cancer example, I have Epilepsy (seizure disorder). Seizures are perfectly nature. When the neurons go off spontaneously, eventually it gets back on it's course. However, it causes unhealthy affects for the brain if one has a seizure too long (from unconsciousness, stroke, or death) or two little but for many many years (eventually deforming the brain-as per my case but I had the big ones too so it was a double wammy). That's what I consider unnatural or maybe unhealthy? not because the neurons go off track but because the body "isn't supposed" to do that.
Likewise with cancer. We develop cancer (if I'm getting my medical info correct) when what is it, the our blood cells or white blood cells stop splitting as usual. It causes ill affects after awhile. It doesn't go on track, unfortunately; and, I'd say it's unnatural for the body because of it's affects that the body (like seizures) are not set or created to make. If that be the case, everyone would have seizures and cancer.
I can't compare to much with male/male actions because it doesn't cause ill affects like cancer and seizures do. Unlike cancer and seizures that may develop without cause or with ill cause say get hit in the head (eventually causes seizures) cant think of a cancer example, male/male actions don't have those motivations (unless someone is getting abused or rapped.)
But its like cancer and seizures that are not made for the body to just automatic do, or else everyone would develop cancer and seizures, likewise with specific actions between two males. It has nothing to do with why (or the cause of the cancer/seizures) nor what's the meaning (love or lust or is it leukemia/is it psychomoto or gram mal seizures), it's just that action, however short or long lived, is not where and how the body is made to perform (like seizures aren't made for the brain to make the healthy neurons go haywire).
Doctors judge seizures and say what's unhealthy (not normal) and what's not all the time. In male/male actions I only see the religious do that. It does't bother me in that way at all. My other example with the toys at Toys R Us-I feel the same way.
Not singling males here and it has nothing to do with homosexuality, just the action.
Weird. Well, regardless of why and what for, my point still applies above. However, I learned something new.