ZYGOTES & BLASTOCYSTS : Human enough to protect?

As debates over stem-cell research and cloning roil on, proponents of scientific research ask their opponents: "But why do you want to protect human zygotes, blastocysts, and embryos from manipulation or loss? How can you care about the inviolability of these 'clumps' of developing cells, 'no bigger than the period at the end of this sentence'?"

But why is size an issue when there is so much inherent developmental capacity? Surely size in a world of quarks, quantum events, and neutrinos is relative. In the microrealm a zygote and blastocyst can appear pretty gigantic. Scientists who describe the big bang claim that at its beginning the whole universe was many times smaller than a single fertilized human cell.

Human zygotes also have a long lineage. They are the incredibly developed endpoints of millions of years of evolutionary change. The active genetic information in the microscopic initial stages of human life is as dynamically potent as a nuclear explosion. Replaying the movie of every human life brings you back to these beginning cells with their specific human characteristics. After all, it is this very capacity for potential that makes scientists want to manufacture, dissect, and destroy embryos in their research.

When George W. Bush announced his ban on new embryonic stem-cell research, he used the image of a snowflake to call attention to the valuable uniqueness of each nascent life. But this image doesn't go far enough. Each zygote's dynamic uniqueness makes it a natural wonder of the world, far surpassing Niagara Falls or the Grand Canyon.

As evolutionary biology has progressed in understanding the developing saga of human life, it has also honed our awareness of our common genetic heritage. We share an identity as one species. Each instance in time of embryonic human life is related to all the rest of the human family, and not just to its progenitors. The human species lives from generation to generation as an interdependent unitary whole. How misguided it is to think it acceptable to divide humankind into bits and pieces of disposable property.

So far as we know, life as complex as ours is unique in the universe. From a cosmic space/time point of view, full to bursting with millions of galaxies, the duration of the existence of any living member of the human species--embryo or Roman emperor--appears as an amazing flicker of light.

Yet I think the evolution of our vulnerable species in a mega-universe explains away another accusation made against defenders of nascent human life. Proresearch types argue that since people don't mourn or provide funerals for the large numbers of spontaneously aborted fertilized zygotes, zygotes cannot be considered to have value equal to other human lives.

This argument ignores the 100 percent mortality rate of human beings, and the fact that people do not mourn the thousands of undeniably adult lives lost in distant floods, famines, or volcanic eruptions. Our race has evolved in small groups with limited cognitive and emotional capacities. We can mourn only those familiar intimates we have known. Naturally no one (outside of disappointed women in infertility clinics) mourns lost embryos. But being unmourned, unknown, or unwanted does not render human life valueless.

Fortunately, human beings have evolved the moral understanding to grant the inalienable dignity of other members of the human family who radically differ from themselves. Strong and competent adults can accept their moral obligation to protect the fragile and vulnerable--no matter how immature, impaired, demented, diseased, or dying. Dependency and the need for mutual care mark the whole human life cycle, from conception to death. Humankind should be afraid of the bitter consequences suffered from drawing exclusionary lines to determine which human lives aren't worthy of protection.

All right, I know, slippery-slope arguments are not philosophically elegant, but they do carry force in practical affairs. Limiting the imperative to experiment and destroy in a good cause has already been proved nearly impossible in arenas such as science and warfare. Creating embryos to destroy them eventually for the sake of more knowledge already seems quite acceptable. And then, inevitably, on to the next frontier?

It is disappointing that many Catholic thinkers can give a green light to experiments with human life. They are not convinced that embryos are human enough to protect, because they do not meet developmental criteria that hark back to medieval philosophical categories of thought. Some of these thinkers do not grant that in today's biology, activated genetic information is what we mean by form. By viewing embryos as individualistic entities, isolated and unembedded in evolutionary history and species identity, these thinkers would deny them equal moral status, at least until fourteen days, or implantation, or some other arbitrary milestone. Too bad. Snowflakes need no protection, but human embryos do.