Abortion and a logical disconnect

I know that I have some pro-choice readers, and I’m hoping that I’ll be able to garner enough attention to this post to answer a question I’ve had rolling around in the back of my head for some time.

I’m “pro-life” or “anti-abortion”, or whatever you want to call it. I’ve been at various levels of the pro-life movement my whole life, from active protesting and participation in The Walk for Life when I was younger, to today where I’m still opposed to abortion – I just don’t go yelling about it anymore.

I’ve debated abortion proponents at different levels, from high school to college and I still occasionally tussle with people today, although again without the frequency and passion that I used to.

So, here’s my issue that I’m hoping someone can coherently explain to me. I support a woman’s right to control what goes on with her body; this is why I’m all for birth control and proper sexual education, condom use, etc. My problem is that I don’t feel that the lifeform that’s growing inside a pregnant woman falls under the domain of “controlling your body”. That’s the basis for my inherent disagreement – from an idealogical standpoint independent of any religious beliefs, that “fetus” is a person. It’s DNA is not the same as the mother’s, although it shares some parts.

What I am clumsily trying to say is that I do not understand how a woman’s right to control her own body (which is fine) extends to termination of a body, or mass of cells that aren’t a part of her body, although they exist inside her body.

Logically, I can’t really see a difference between aborting a baby, and waiting until it’s born and then killing it. In both circumstances, the person being killed had no chance to defend themselves, and no opportunity to offer their opinion or consent.

The only way I could justify that sort of behavior is if I believed that while inside the mother, a baby was not a person, and in fact nothing more than a lump of tissue with different DNA that magically becomes a person after birth. I find that belief to be slightly intellectually dishonest, but that’s just me.

So, to restate – how exactly can a pro-choice person justify the termination of a “mass of cells” that does not belong to the mother?