I became interested in the topic
for this essay rather indirectly. I have been working on writing
a science fantasy story which has as one of its elements the
manipulation of X chromosomes. I want the story to be as accurate
as possible with respect to the science aspects. When I read the
two SCIENCE articles referenced
in the item, I realized that
what I had planned
regarding the consequences of the manipulation might not work because
of the possible rejection effect. I then tried to find out by a
web search what I could about what is known concerning such rejection
effects, but I could not find anything.
After sending email to
about a dozen places that perform IVF surrogate procedures and asking
for information, several correspondents directed me to the CDC National
Summary and Fertility Clinic Reports. Only the
report for the year 2000 (Section 5) had data comparing the cases
relevant to the essay.
Using the nomenclature of these
reports,
the relevant categories are: (1) Gestational Carrier using Fresh
Nondonor ova and embryos, and (2) Fresh Nondonor Non-gestational
Carrier. What is desired is comparing data for these two
categories where all other factors are equal. Unfortunately, this data in the 2000
report was not complete enough to be useful.
The statistics presented in Figures 39 and 40 in the 2000 report show
that the category (1) cycles have a higher success rate than
the
category (2) cycles. Superficially, this would seem to disconfirm the
conjecture. However, it seems likely that "all other factors" are not
equal in the presented data. One set of additional useful data would be
how the success rate varied with the age of the gestational carrier.
Other useful data would be the age distribution of the gestational
carriers. No data about the ages of gestational carriers is given in
the reports. Another possible unequal factor that I need to take into
account is the elimination from the category (2) statistics those
cycles where the mother has comorbidities, such as for example
diabetes, that may reduce the likelihood of success.
One correspondent, Sean Tipton,
Director of Pubic Affairs, ASRM DC, indicated that I was unlikely to
find the data I needed, but he suggested where he thought was the most
promising site to contact. However, so far I have recieved no
response from that site.
So, for the purpose of the current version of this essay, I am assuming
that there is a likely
rejection
effect, and this essay’s purpose is to present an idea that may or may
not be useful to some potential readers.