Human stem cell research – Religious Tolerance

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There are about 360 fertility labs in the U.S. that conduct in-vitro fertilization procedures. They typically extract about 24 ova from each woman client, and fertilize them with a male donor's sperm -- typically her husband's. Two to four of the resultant embryos are then selected and implanted in her womb in the hopes that one will develop and continue a pregnancy to term. Some clinics discard the excess embryos or use them for training purposes. Most clinics deep-freeze the other 20 or so embryos in liquid nitrogen. Some may be used in the future if no pregnancy resulted, and a repeated attempt at impregnation is desired. A few are donated by the couple that "owns" them to another infertile couple. But this is rare, because most clients dislike the idea of having what is in effect their child living in another family. Most become spare, permanently unneeded, frozen embryos .

Past estimates of the number of frozen embryos in the U.S. vary from 100,000 to 188,000. However "experts said that was little more than a guess, and even if it was accurate at one time, it is long out of date now. Plans for what would be the first careful national accounting are being prepared now by the reproductive medicine society." 1

Some clinics keep the embryos alive in liquid nitrogen indefinitely -- or at least until an operator error or equipment malfunction kills them. One source says that about 25% of frozen and thawed embryos do not survive between the first and second impregnation procedure. This loss rate appears to be related to the quality of the freezing and thawing processes, not to the length of time they have remained frozen. If an embryo survives the freezing process, it will probably remain viable for decades. Some have speculated a lifetime of hundreds of years if kept frozen. Experiments on mouse embryos showed no loss in their ability to produce pups after having been frozen for 25 years. Human embryos would probably behave similarly. 13

Other clinics simply discard or destroy the spare embryos. Some embryos are simply flushed down a sink drain. Some are transferred to a medical waste bin where they are later incinerated. Some simply expose the embryos to the air and let them die; this normally takes four days or less.

One source speculates that hundreds of thousands of unused embryos have been destroyed in fertility clinics. 1 This compares to the few dozen of embryos which have had their stem cells removed and used to create stem cell lines in the lab. Surprisingly, nobody seems to care or object. Even pro-life groups appear to be silent on this matter.

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