Monitoring Stem Cell Research 
89 
not therefore justified in doing deliberately. Indeed, the rate of 
natural loss of live-bom human beings is 100 percent, but that 
does not justify their killing. And, they argue, even if one were 
permitted to analogize the deaths of frozen embryos in vitro to 
the embryonic wastage in vivo, in neither case were the em- 
bryos lost destined or created for anything other than their 
procreative end. In contrast, they argue, using embryos for re- 
search bears no relation to their natural direction or trajectory. 
Critics also argue that the character of our reaction to the natu- 
ral embryonic death does not justify our practice of destmctive 
embryo research. For they believe that a creature’s moral 
worth is not dependent on the emotional reaction of others to 
its death. The absence of moral sentiment does not imply an 
absence of moral obligation (nor a right of adverse intervention 
in a naturally developing human life). Moreover, critics con- 
tend, it is not clear how many of these "natural losses” were in 
fact failures of the fertilization process, so that there was never 
a unified, integrated organism in the first place, and thus never 
the loss of a human embryo. It is also unclear, they argue, how 
much of the supposedly "natural” loss rate is actually due to 
contingent and changeable factors such as environmental pol- 
lution, pesticides, or endometrial problems, and so is not sim- 
ply an unavoidable fact of embryonic existence. 
3. Prediction of Non-Viability of Embryos. 
Some people, hoping to get around the moral dilemma of 
destroying even "unenabled” embryos, seek to identify a sub- 
set of embryos that might reasonably be regarded in advance 
as non-viable. One proposal has involved the possibility that 
cloned human embryos, created by somatic cell nuclear trans- 
fer, may prove to be non-viable or unable to develop beyond a 
certain point (biological evidence that this may be the case is 
presented by Rudolph Jaenisch in appendix N) or may even, 
by their nature and origins, simply not constitute the equiva- 
lent of human embryos. If this turns out to be true, it is further 
argued, it might be possible to use them without arousing 
some of the ethical dilemmas that accompany the use of oth- 
erwise potentially viable human embryos. Others point to a 
possible sub-group of those embryos currently frozen in stor- 
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