While drug companies await new assays and therapeutics based on human embryonic stem (ES) cells, the debate over their use rages. By now, you will likely have heard about or possibly read two papers that appeared online in Nature last month that muddy the debate. In their own ways, each paper tries to address the concerns about destroying human life by doing a bit of an end run around the controversy.
In one proof-of-concept paper, researchers at Advanced Cell Technology, the University of Wisconsin and Wake Forest University adapted a method used in the in vitro fertilization (IVF) industry to extract single cells from early-stage mouse embryos. These single cells, which are used in IVF for pre-implantation genetic diagnosis, form the basis of an ES cell line. The remaining embryos, meanwhile, remains perfectly viable and could eventually lead to living mice. In this way, the authors write, the new method "could circumvent the ethical concerns voiced by many."
In the second proof-of-concept paper, again in mice, researchers from the Whitehead Institute avoid the issue of embryo viability altogether by genetically engineering embryos developed in nuclear transplantation experiments that are incapable of uterine implantation. Because the embryos could therefore never be considered as viable candidates for birth, they are ripe candidates for ES cell line development. The authors note, however, that because they are genetically modifying an embryo, "this approach may not solve the ethical dilemma."
From a purely scientific perspective, each team should be applauded for their efforts to advance science and our understanding of human health. From the perspective of the current ES cell debate, however, both teams (and many scientific commentators) have failed to grasp the underlying problem of the debate—a foible common to much of the scientific community.
Simply put, this is not a rational debate based on quantifiable pros and cons. This statement is not meant to be derogatory, for there can be few discussions that are more visceral to humans everywhere than how we define life, and in particular, human life.
By its very nature, science sees all questions as issues of measurement and analysis. Put a barrier in front of us and we will work to overcome that barrier using our arsenal of experimental and interpretative tools. The assumption, therefore, is that if someone places conditions or limits on experimentation, simply addressing those conditions will be sufficient to win the argument.
This doesn't appear to be the case with the ES cell debate. Maintaining embryo viability or making embryo implantation moot are rational responses to an irrational discussion. For this reason, they are not likely to cause significant movement in the debate.
From the other side of this debate, the basic underlying challenge is that it involves experimentation on humans who are incapable of speaking for themselves, let alone signing consent forms.
As long as we are incapable of absolutely and legally defining the starting point of human life as a community, this debate will continue to rage, much as the Roe v. Wade question continues to haunt the American legal system with every new Supreme Court nomination and national election.
Each person, of course, will have his or her opinion on when an embryo created by the union of human gametes becomes a human, whether that opinion is based on science, religion, personal conscience or a combination thereof. And I am confident that no amount of scientific wrangling will shake this opinion.Regardless, in my opinion, there is no question that the science should proceed. I just want to make sure that no one is too terribly surprised when the response to these papers is that the people arguing the other side simply raise the bar a little higher.