I'm always curious to learn how people define being "human" in terms of the abortion debate. For me, it's pretty logical and pretty simple. I believe life starts at conception. At that point, you have a unique individual with a unique set of DNA.

In today's Washington Post, columnist Michael Kinsley makes a disturbingly narrow definition for what it takes to be human.

Abortion is a tough question for most people, but the related issue of embryos and medical ethics can be a lot easier. It can be solved without a lot of stagy agonizing, and without trivializing other people's moral concerns, even ones you may not share. An embryo has no feelings, no self-awareness, nothing that would give anyone a concern about its welfare except for its potential to develop into something we recognize as human. Religion can give you that concern as a matter of faith, but government policy should not be based on this belief any more than on the religious belief of some people that plants have souls.

So, for you to be human, worthy of protection under our constitutional system you must possess to qualities:

1.) Have feelings.
2.) Have self-awareness.

According to Kinsley's logic, since an embryo has neither of these (I'll concur on the self-awareness aspect, but I'm not so sure on the feelings -- it depends on your definition of "feelings") it can be used for research purposes.

So, how does Kinsley reconcile these with the criteria with, say an individual who has been injured in a car accident and is in a vegetative state? The person may or may not be brain dead. They certainly have no "feelings," (i.e. they don't respond to pain) and they exhibit no evidence that they are self-aware, so are medical experiments OK on these people?

This example is farther out there, but how about a profoundly mentally retarded leper?

My definition of "being human" is as broad as logic permits. If you have the DNA that defines you as a homo sapiens, then, no matter what your level of development -- from blastocyst to elderly invalid -- you should be accorded the same rights under the Constitution.

When you artificially narrow the definition (in Kinsley's case, in hopes of benefiting himself), you are always in danger of excluding individuals whom you do not intend to exclude.

What bothers people is that there is no clear moment in human development when an embryo becomes a fetus or a fetus becomes a person. The gradual way fetuses take on aspects of real personhood is what makes the second line so controversial. The first line is not nearly so fraught with implications.

Here, Kinsley falls into the semantics trap. He's chosen three terms: embryo, fetus and person. The first two are stages of development, the third is not. Many would argue that an embryo, fetus, infant, toddler, child, pre-teen, adolescent, teenager, young adult, 20-something, 30-something, middle-aged, senior, elderly are all "persons."

Kinsley argues that the "first line" (embryo to fetus) is not controversial. It's not controversial to him. It's not controversial to people who narrow the definition of what is human. For many who are pro-life, a person's stage of development is irrelevant. Kinsley argues that the degree of similarity to a normal human being is what is important. An embryo doesn't "look" human, so it's not worthy of protection. How about someone badly scarred by fire? How about someone like "The Elephant Man?"

I'm sympathetic to Kinsley's situation. Kinsley, like many others, suffers from Parkinson's disease, but the answer is not to kill other "persons" in the hope for a cure.

I caught a few minutes of Leon Kass, head of the President's Council on Bioethics, on CSPAN earlier this week and he was addressing a point that Kinsley is making about the "line" being crossed.

Kass posed the hypothetical: what would we do if scientists discovered some benefit from having a human grow for two months (in or out of the womb) and then destroyed for research, or perhaps, cure some disease. Is that OK? How about killing a 2-year-old to get a kidney?

Kass' point is once you've crossed the first line, using human embryos/blastocysts/fetuses, why stop? And when do you stop?

*RELATED NOTE* I'd meant to point this out last week, but Post columnist George Will had an excellent article on the law and the unborn. If you haven't seen it, it's worth a look.

The key line: "Abortion kills something. What is it?"