I am not making the argument that natural childbirth is a superior form of childbirth, nor ought it be preferred in all cases because it is the way things work

I am not making the argument that natural childbirth is a superior form of childbirth, nor ought it be preferred in all cases because it is the way things work normally. I am making the argument that saying that that particular form of procreation is 'arbitrary' is ridiculous. It's clearly not arbitrary: it is the way healthy, normal humans have children, and is the form of childbirth that was selected by evolution. That may or may not mean that it should be preferred by couples (though in reality, it certainly seems to be) but that's a far cry from saying there is nothing particularly unique about it. Of course, by assuming it is an arbitrary form of childbirth, which it's not, you fall into the trap of claiming that it should not be given undue weight for couples looking to have children. I'd argue that the burden of proof is on you to show this to be the case, since after all, you are (most likely) living, breathing proof of the multi-generational long term effectiveness of this method. edit: Also, as an aside, your citation of an appeal to nature logical fallacy is only relevant if the argument being made is that something is inherently good because it is natural, full stop. When it comes to something like procreation, you can clearly make the argument that humanity itself is an existence proof of the effectiveness of that natural mechanism, therefore for that particular case (or really, any case where evolutionary pressure has resulted in a objectively effective solution to a problem) that logical fallacy does not seem to apply.