Doesn't stop it being a natural occurance. And in the example you give, there's a measurable harm when applied to human mating (hence why it's generally not a good thing). There's no measurable harm in homosexual sex.
Mesuraeel harm has nothing do do with it being natural or not.. which is the point of this discussion.
But, let's dwell into this, shall we?
What is "mesurable harm"? And who mesures it? Who defines what is harmfull?
Obviously, the spiders and many other creatues KNOW what will happen but they do it anyway.
So obviously they consider that it is worth it and not harmfull for their species.
You can say - it must be harmfull as soon as a result someone dies!
Well, everyone dies as a result of life. Everything dies, it's just a matter of how and when.
so dying while doing something you like isn't exactly what I would call harmfull.. LOL
Well, that was a remarkably idiotic statement. Say how homosexuality causes actual, real harm to people. Not the perceived 'harm' of the intolerent minded who can't stand, can't bear to have someone - shock! -
different, because that sort of harm is pretty much defined on the same basis as racism or bigotry. Measurable harm (m-e-a-s-u-r-a-b-l-e;
capable of being measured; "measurable depths") is a harm which can be defined in rational, logic manners. For example, theft is measurable harm as it firstly deprives an individual of a material and useful good, and also as it damages the societal system of work-bargain.
Let's take sexual cannibalism, as I found a
rather interesting link on it. Now, there's obvious measurable harm to the male.... but there's also a species-wide benefit (rather than harm) to this behaviour, as the paper details and as you noted (perhaps without understanding the ramifications), which explains the evolutionary benefit and reason for existence.
Now, whilst there probably isn't a species wide benefit (perhaps... although if it is genetic, then perhaps there is a benefit which will be identified when the genes for homosexuality are) to human homosexuality, there isn't any species wide harm either; certainly not one natural selection would remove (errr, obviously, as it's pretty ubiquitous across much of human history).
