Mr. Chairman and members of the Subcommittee on Labor, Health and Human Services, Education, and Related Agencies, my name is Michael D. West and I am the President and Chief Executive Officer of Advanced Cell Technology, Inc., a biotechnology company based in Worcester, Massachusetts. A copy of my curriculum vitae is presented in Appendix A.
INTRODUCTION
I am pleased to testify today in regard to the new opportunities and challenges associated with human embryonic stem (ES) cell and nuclear transfer (NT) technologies. I will begin by describing the bright promise of these twin and interrelated technologies and then attempt to correct some misunderstandings relating to their application in medicine.
It may be useful to point out that I think of myself as pro-life in that I have an enormous respect for the value of the individual human life. Indeed, in my years following college I joined others in the protest of abortion clinics. My goal was not to send a message to women that they did not have the right to choose. My intent was simply to urge them to reconsider the destruction of a developing human being. Despite my strong convictions about the value of the individual human life, in 1995 I organized the collaboration between Geron Corporation and the laboratories of Dr. James Thomson and John Gearhart to isolate human embryonic stem cells and human embryonic germ cells from human embryos and fetuses respectively. My reasons were simple. These technologies are entirely designed to be used in medicine to alleviate human suffering and to save human life. They are, in fact, pro-life. The opponents that argue they destroy human lives are simply and tragically mistaken. Let me explain why this is the case.
We are composed of trillions of individual living cells, glued together like the bricks of a building to construct the organs and tissues of our body. The cells in our bodies are called “somatic cells” to distinguish them from the “germ line”, that is, the reproductive cells that connect the generations. We now know that life evolved from such single-celled organisms that dominated all life some one billion years ago.
Figure 1. The Distinction Between the Life of Cells and the Life of an Individual Human Being in the Human Life Cycle. Biological, that is, “cellular life” began with the origins of life on earth. The beginning of the life of an individual human being is linked to the appearance of somatic cells, that is, cells committed to form the human body.
Therefore, in answer to the question of when life begins, we must make a crucial distinction. Biological life, that is to say, “cellular life” has no recent beginnings. Our cells are, in fact, the descendents of cells that trace their beginnings to the origin of life on earth. However, when we speak of an individual human life, we are speaking of the communal life of a multicellular organism springing from the reproductive lineage of cells. The individual human life is a body composed of cells committed to somatic cell lineages. All somatic cells are related in that they originate from an original cell formed from the union of a sperm and egg cell.
The fertilization of the egg cell by a sperm leads to a single cell called the “zygote”. From this first cell, multiple rounds of cell division over the first week result in a microscopic ball of cells with very unusual properties. This early embryo, called the “preimplantation embryo”, has not implanted in the uterus to begin a pregnancy. It is estimated that approximately 40% of preimplantation embryos formed following normal human sexual reproduction fail to attach to the uterus and are naturally destroyed as a result.
Figure 2. The Blastocyst Stage of the Preimplantation Embryo. At the blastocyst stage of the preimplantation embryo, the external cells called the “trophectoderm” are destined to attach to the uterus and form the placenta. The remaining cells, the Inner Cell Mass (ICM) are completely undifferentiated and have not committed to any somatic cell lineage vs. the germ-line.
From the above it should be clear that at the blastocyst stage of the preimplantation embryo, no body cells of any type have formed, and even more significantly, there is strong evidence that not even the earliest of events in the chain of events in somatic differentiation have been initiated. A simple way of demonstrating this is by observing subsequent events.
Should the embryo implant in the uterus, the embryo, at approximately 14 days post fertilization will form what is called the primitive streak, this is the first definition that these “seed” cells will form an individual human being as opposed to the forming of two primitive streaks leading to identical twins. Rarely two primitive streaks form that are not completely separated leading to conjoined or Siamese twins. In addition, rarely, two separately fertilized egg cells fuse together to form a single embryo with two different cell types. This natural event leads to a tetragammetic chimera, that is a single human individual with some of the cells in their body being male from the original male embryo, and some cells being female from the original female embryo. These and other simple
Figure 3. The lack of Individuation of The Blastocyst Stage Embryo. Lessons from nature indicate that the blastocyst-stage preimplantation embryo has not individualized. On the left fraternal or nonidentical twins form from independently-fertilized egg cells. Identical twins form from a single ICM breaking into two ICMS (center diagram) or by two primitive streaks forming on one ICM (right diagram).
lessons in embryology teach us that despite the dogmatic assertions of some theologians, the evidence is decisive in support of the position that an individual human life, as opposed to merely cellular life, begins with the primitive streak, (i.e. after 14 days of development). Those who argue that the preimplantation embryo is a person are left with the logical absurdity of ascribing to the blastocyst personhood when we know, scientifically speaking, that no individual exists (i.e. the blastocyst may still form identical twins).