An excerpt from "Square Peg: Confessions of a Citizen Senator," reprinted with permission from Basic Books.

As recently as the late 1700s, the well-known English theologian and cleric Edward Massey delivered a sermon titled "The Dangerous and Sinful Practice of Inoculation." It was given at a time when religious leaders and scientists were arguing over the use of vaccines to prevent the spread of smallpox. According to Reverend Massey, "Diseases are sent by Providence for the punishment of sin, and the proposed attempt to prevent them is a diabolical operation."

Then, as now, unfortunately, rhetoric was swallowing the debate. Both sides focused more on the traditional positions and arguments about abortion and cloning than on the more difficult and unique scientific and philosophical issues at the very heart of the new research. In Congress, the issue first came to a head in 2001 over the question of whether President Bush would permit federal funds to be used to fund research on stem cells derived from surplus in vitro fertilization embryos. Both sides weighed in heavily, and the lobbying was intense.

I struggled with what to do. As a pro-life senator, I had played a leading role in numerous fights over abortion, and many of the arguments being made by some of my colleagues, such as Senator Brownback and Representative Chris Smith, resonated with me both personally and professionally.

Given my voting record and position on abortion, the obvious political course was to follow the lead of the Right-to-Life community and support a complete ban on this kind of research. It would be far easier-and better for my future elect ability-to support a ban than to endorse this most promising branch of regenerative medicine. What this position would not do, however, was help the millions of people suffering from serious chronic diseases.

Moreover, the passionate defense of life should not stop at birth. We have as profound an obligation to a child outside the womb as we do to one inside. To me, an advocate for life has to consider not only our obligations to a group of cells with the potential for life but also our obligation to our fellow citizens-men, women, and children-who will face untold suffering and lose many years of life unless there is a medical breakthrough.

Using the information I had gained from all my meetings, I tried to work through the problem in a logical manner. First, was an unimplanted egg fertilized through in vitro fertilization in fact a person? Put another way, was an artificially fertilized egg, frozen and stored in a refrigerator, the equivalent of an embryo or fetus developing in a mother's womb?

Several churches argue that life is sacred from the moment of conception, regardless of how that conception occurs. A fertilized egg contains the entire human genetic code and has the potential to grow into a person. Therefore, to them, it is spiritually and ethically a human being.

Other religions, however, base their support of embryonic stem cell research on their obligation to assist not just the unborn but the whole spectrum of life, especially when assistance cannot be provided by any other means. To them, ignoring this opportunity would be immoral and unethical.

There is a third perspective, the so-called "developmental" view of life, that an early embryo, before the formation of the primitive streak that will eventually become the spinal cord and brain, does not enjoy the same legal protections as a person. This is based in part on the assessment by some scientists that for the first fourteen days, a fertilized egg is little more than a jumble of cells.

All three positions have thoughtful and sincere supporters. For many, the right interpretation is based on both religious faith and understanding, made all the more difficult as science has forced religions to review their positions on life and creation.

For me, human life begins in a mother's nurturing womb and is impossible without it. The blastocysts used for embryonic stem cell research, whether they are developed through the somatic cell nuclear transfer process or are unused embryos from an in vitro fertilization clinic, are not the same as a person or a fetus. A frozen embryo in a laboratory refrigerator is more akin to a frozen egg or sperm. While each has the potential to contribute to human life, no frozen egg, sperm or embryonic cell can reach personhood absent a mother's womb. There is little debate over the ethical or moral consequences when these are discarded, just as there are few objections when an in vitro clinic discards unused blastocysts.

Oddly, the controversy seems to arise only when blastocysts already scheduled for destruction are used instead for scientific research. As Dr. Louis Guenin has pointed out, stopping embryonic stem cell research does not guarantee that one more baby will be born.2