As far as the human body is concerned, it's perfectly natural for a woman to be artificially inseminated. The only thing "unatural" is that she didn't get bashed by a guy
If you know anything about survival of the fittest and natural selection, you would know that people who cannot reproduce are genetically weak. It is not natural to pump someone full of hormones so they can have a child. They weren't meant to have one. That's why you have all those crazy quadruplets and shit....it's not natural and to condone a genetically created child makes no sense if your stance is about nature taking it's course.