by William Cutrer, M.D. and Sandra Glahn, Th.M.
“When I use a word,” Humpty Dumpty said in a rather scornful tone, “it means just what I chose it to mean—nothing less, and nothing more.”
“The question is,” said Alice, “whether you can make words mean so many different things.”
—Alice Through the Looking Glass, Lewis Carroll
Alice tried to convince Humpty Dumpty that words have whatever meaning we assign to them, and it would appear that some modern researchers have followed suit. When talking about human embryos, confusion over precise terminology causes many disagreements among those concerned about current medical advances. However, if we value the sanctity of human life, we need to understand some terms so we can best articulate our position.
Embryo. In the Wonderland that is life, an embryo is the very early stage of human development. It is separate from the portion of the developing group of cells that become the placental or supportive tissue. After the sperm penetrates the egg and the chromosomes from the father and mother align in the egg, fertilization has occurred. In a natural cycle, this event takes place in one of the female’s fallopian tubes.
Pre-embryo. Many refer to the resultant living, growing tissue as a “pre-embryo,” because as this developing ball of cells grows, precisely which of the cells will become the baby and which will become the supporting, nutrient delivering structures is unknown. In fact, several of these early cells could die and the pregnancy can still proceed on the basis of the health of another cell.
Unfortunately, some crafty Alice-types, in an effort to get around those who oppose research on the human embryo, have “creatively” used the term “pre-embryo” to convince pro-lifers that life has not yet begun. However, that is not the case.
The earliest cells are believed to be “totipotential.” That is, each cell can generate all the tissues necessary for a baby’s development. How the one cell is “chosen” remains unclear. Yet while we can’t tell which cell will develop into the infant, it is not a problem for a sovereign God who “weaves us together in our mother’s womb” (Psa. 139). Clearly, no genetic material is added after this fertilization moment, and the cell from which all of the infant’s cells will derive exists within this cell mass.
Implantation. In approximately seven days, the growing collection of cells invades into the wall of the uterus (womb), an event technically called “implantation.” Some medical resources define this process as “conception”—a definition carried forward from the days before much was known about this complex and beautiful process. By current common usage, the term “conception” is often used interchangeably with fertilization, so it becomes critical that the words are clearly understood. Why? Because by the previous technical definition of “conception,” a woman could use a method of “contra-ception” that destroyed the growing mass of cells before the seven-day implantation event. To those who understand that all of life’s genetic machinery originates with the fertilization event, such an intervention—after fertilization but before implantation—would be an abortion, not a pregnancy-preventing method. The manufacture of the term “pre-embryo” further desensitizes individuals to the humanity and personhood of fertilized, dividing eggs created by assisted reproduction techniques. In this case, an embryo by another name is easier to destroy. Voilá! Alice has succeeded.
For some, the destiny of frozen (cryopreserved) embryos presents major ethical concerns. Using the term embryo to describe the tiny human being from its fertilization event, whether or not we can identify the precise cell of origin, gives proper significance to its presence. Decisions about the ethics of many of the available technological advancements hinge on understanding and communicating precisely using the unique vocabulary of the specialty.
Defining when life begins. One more thing—in cloning (by fusion, reference past article), there is no actual moment of “fertilization.” In this process egg and sperm are not joined, but rather the nucleus of one cell is inserted into an enucleated egg (that is, an egg with all its genetic material removed) and stimulated to grow. Thus, all the genetic material is extracted from and identical to the “donor” cell. The result would be a new individual with precisely the same genetic makeup as the donor—an “identical twin” perhaps ten, twenty, thirty years or more after the birth of the sibling.
If this type of cloning is possible with humans, as accomplished in sheep, pigs and cows, this new life would begin when the “genetic switches” were reactivated, making this first cell “toti-potential.” The twin would begin from this one cell stage. So in this case, it is unhelpful to say, “Life begins at fertilization.” Rather, it is important to clarify here that life begins at the moment when chromosomes are re-activated. (In this type of cloning, the chromosomes have aligned long ago, but have had portions deactivated.)
If we want to communicate our position, we need to clean up the murky looking-glass of terms to describe life at its tiniest stages so that our words reflect clearly what we mean to say.
Join us next time as we explore further the subject of cloning.