In my last post I spoke about an ethical issue mentioned in passing in a book that examined reproductive medicine from the perspective of organizational theory: that in this age of evidence-based medicine some of the most vital decisions—who lives and who does not—are based primarily on subjective grounds. A second issue mentioned in the book that I found greatly disturbing was that the use of ICSI—intracytoplasmic sperm injection, a procedure now readily accepted and utilized in reproductive medicine–potentially creates a “new race” of persons.
As quoted in the book, from a professor and entrepreneur of a British infertility clinic, “…they [children born of ICSI] are of a different kind, another race than us.” How is that so? In normal fertilization, only the head of the sperm penetrates into the egg; the mitochondrial portion including the male mitochondrial DNA is left behind. Consequently the fertilized ovum contains only maternal mitochondria. But with ICSI, the entire sperm is introduced into the heart of the ovum, along with the male mitochondrial DNA and the potential for the incorporation of this material into the offspring. As this same professor is quoted as saying, “That does not mean it is dangerous but it is on the other hand not what happens during normal fertilization. So there is this little question mark and it is (sic) interesting to see what happens when these children are starting to reproduce.”
A little question mark indeed! Studies are inconclusive; beliefs vary. According to Australian researchers, “The elimination of sperm mitochondrial DNA is essential for the functional integrity of the offspring, as sperm mitochondrial DNA appears to harbour a large number of mitochondrial DNA defects.” This issue becomes particularly relevant given the recent surge of interest in mitochondrial disorders and the means of preventing them through the use of donor eggs. Many believe that the paternal mitochondrial DNA undergoes ubiquitin degradation, supported by studies that fail to demonstrate expected levels of paternal mitochondrial DNA in offspring, but the numbers studied have been small—six, to be exact! Other studies have documented its presence in embryos, and suggest that it is protected by the plasma membrane surrounding the mitochondrial sheath. Could it be that it becomes sequestered in certain tissues? There have been case reports of severe mitochondrial myopathy due to a mitochondrial defect that was paternal in origin.
To further complicate matters, ICSI has become a standard, and hence, unindicated, procedure. Once used only for male factor infertility for which it was of great benefit, it is now used commonly because it was found to “a little bit more effective.” Whereas male factor infertility affects only about 20% of infertile couples, ICSI is used in 60-89% of in-vitro cycles. As an anonymous clinician stated, “It will be interesting to learn if the boys have inherited this male factor because that has not been studied…We do not know what is happening to all these children.”
Interesting indeed! Such attitudes, which permeate this field, are cause for alarm. Economic interests and “freedom of choice” too often overrule patient safety; and expediency is allowed to trump prudence. Not surprisingly, most of these questions arose after ICSI became standard practice. But “cutting edge” technology is often a double-edged sword, cutting both ways. Are we iatrogenically creating long-term problems for short-term gains? Is a greater good for some going to prove to be a greater harm for many? Are we creating a new race, a new problem…or both?