Introduction 
11 
than embryonic ones, as we have noted, because the former 
can be collected without lasting harm to the donor. 
D. Cord Blood Stem Cells 
Though clearly a type of non-embryonic stem cell, cord 
blood stem cells deserve some special mention. Blood found in 
the umbilical cord can be collected at birth and hematopoietic 
stem cells (and other progenitor cells) isolated from it. It has 
been proposed that individually banked cord blood cells may, 
at some later time, offer a good match for a patient needing 
stem cell-based treatments, whether the individual cord- 
blood-donor himself or a close relative, and in unrelated recipi- 
ents may require a less exact genetic match than adult bone 
marrow.* ''' 
* Several companies in the United States have sprung up to offer commercial 
storage services for cord blood in case the child or a closely genetically- 
matched sibling should later need the stem cells contained in the cord blood 
for medical use. It is unclear whether individual banking of cord blood will 
turn out to be valuable. It may turn out that, for the vast majority of people, 
the cells are never needed, or that, when therapy is needed, the stored cells 
are found to be imsuitable or incapable of meeting the need in the time re- 
quired. At the same time. Congress has recently allocated funds to create a 
national non-commercial cord blood bank potentially available to all patients. 
The authors of the legislation argue that a national bcink would have cord 
blood of many different types, increasing the odds that a patient would find 
a match. 
^ The possibility of therapeutic use of cord blood stem cells has raised a seri- 
ous question unrelated to the ethics of stem cell research: whether parents of 
a sick child may morally conceive another child, of genetic make-up appro- 
priate for providing compatible cord blood cells, primarily to treat the first 
child. In generating the second child, a prospective parent or parents might 
screen preimplantation embryos for genetic suitability to provide the cells 
(both compatible blood type and freedom from the genetic disease affecting 
the older sibling). These and other ethical questions surrounding 
preimplantation genetic diagnosis (PGD) go beyond our present subject and 
will not be considered further in this report. 
PRE -PUBLICATION VERSION 
