The reason religion is so powerful

[Mister Agenda]

 It's absurd to think that a cheek cell becomes a human being as soon as we can competenly clone a person from one.

Respectfully, that's an argument from personal incredulity.  That said, I have used the word organism rather than being whenever possible, or have otherwise used them synonymously. And personally, your use of human being sounds more like spirituality than philosophy—a soul for atheists. But I'll stick with the word organism to avoid confusion.

Something can be true and still be absurd to claim. So you're saying that it's reasonable to consider a cheek cell is a person if you can generate a viable clone from it, and the only thing actually needed for something to actually be a human person is that it be a genetically human potentially viable cell.

If you're sticking with the word organism, on what do you base the idea that a pregnant woman should ever be forced to give birth if she's not willing?