Scientists doing the research take a different view [than pro-lifers] of the status of the embryo as it exists before implantation when it adheres to the walls of the uterus.Slack should be fired, either for appalling ignorance about facts of biology or for skewing those facts to justify a controversial research practice.
"To me and to most scientists, the pre-implantation human embryo is a ball of cells," Slack said.
The offspring of many of the cells in that microscopic ball are destined to become part of the placenta. And some carry multiple copies of their genetic material so that two, three or more individuals could be born if all of the copies were to survive.
"You don't have one human individual," Slack said.
"Scientists regard these balls of cells as much more akin to human cells grown in culture or blood banks, or organs intended for transplantation," he said. "They are genetically connected to humans but they are not human beings."
The embryo is "a ball of cells" in the same way that I am a (much larger, differently shaped) clump of cells. But it's not just any ball of cells -- it's an individual organism whose parts are integrated and working together to bring the whole to maturity (radically unlike "human cells grown in culture or blood banks, or organs intended for transplantation"). The human embryo is unquestionably a member of the species Homo sapiens at the earliest stages of development.
In 1981 world-class embryologists testified before a U.S. Senate committee. The official Senate report reached this conclusion:
Physicians, biologists, and other scientists agree that conception marks the beginning of the life of a human being -- a being that is alive and is a member of the human species. There is overwhelming agreement on this point in countless medical, biological, and scientific writings.The report added:
No witness [who testified before the committee] raised any evidence to refute the biological fact that from the moment of conception there exists a distinct individual being who is alive and is of the human species. No witness challenged the scientific consensus that unborn children are "human beings," insofar as the term is used to mean living beings of the human species.One can quote embryology textbooks and dozens of scientific experts to make the same point. For example, Langman's Medical Embryology explains, "The development of a human being begins with fertilization, a process by which the spermatozoon from the male and the oocyte from the female unite to give rise to a new organism, the zygote."
I suspect Slack thinks the fact that the early embryo's cells are still undifferentiated -- and that the early embryo is capable of twinning -- counts against the proposition that the embryo is a whole, individual organism. But that simply doesn't follow.
The evidence clearly shows that the embryo functions as its own organism. And the fact that a single organism can give rise to two distinct organisms -- much like a flatworm cut in half, or an animal or human being cloned via somatic cell nuclear transfer -- does not mean the original wasn't a unitary individual. Again, the scientific evidence says it is.
See this White Paper by Dr. Maureen L. Condic, as well as Embryo by Robert George and Christopher Tollefsen (Ch. 6 deals in detail with "new objections to the humanity of the early embryo").