If I didn't know better I would probably think that any embryos used in research had been collectively plucked from a future of bibs, baby food and spit up by the ruthless and immoral supporters of ESCR, when in reality, any embryo used in research was slated to die before it was donated to research.
Further, those who argue against permitting the use of excess in vitro fertilization (IVF) embryos in research, if you follow their reasoning to its logical conclusion, must also argue for the abolition of IVF as it is currently undertaken.
Increasingly, couples having trouble conceiving are turning to assisted reproductive technologies (ART) in their quest to have children. The most common type of ART is in vitro fertilization (IVF), which involves extracting a woman's eggs, fertilizing them outside of the body in a Petri dish (in vitro means “in glass”) and then transferring the resulting embryos into the woman's uterus with the hope that one of them will implant.
In most cases, however, more embryos are created than are used in the pursuit of implantation - and the right to determine the destinies of those embryos currently rests with couples who produced them. Ultimately, there are three options from which to choose: donate the embryos to another couple, donate them to research, or have them discarded by clinic personnel. There are those who would count leaving them in storage as an option, but storage is just an interim state; all of the frozen embryos will face one of those three aforementioned options eventually. And just so that we are clear, I will say that both donating an embryo to research and simply discarding it result in the destruction of the embryo.
If one believes that it is wrong to destroy an embryo in the course of research, then one must believe that it is wrong to destroy an embryo, period - whether it is in the course of research, or in the course of a day at the IVF clinic. From that it follows that if IVF were to be allowed to continue in an acceptable form, of the current three options available to couples - donate to another couple, donate to research, or simply destroy - the latter two would have to be eliminated, leaving only one option: donating to another couple.
However, that model, even if it were legally defensible, would only be acceptable if no other embryos were harmed in the IVF process - but other embryos are harmed. One IVF clinic describes in detail how the staff sifts through the embryos formed in one IVF procedure and decides which ones are viable for implantation - the others are discarded. And then there is the problem of freezing itself. There is a baseline attrition rate of anywhere from 10-25% when embryos are frozen and thawed. The attrition rate can be lowered by discarding embryos that may be viable under normal circumstances but are judged to be less likely to survive freezing. (Genetics & IVF Institute, Georgia Reproductive Specialists)
So, any way you slice it, if one argues that it is wrong to destroy an embryo in the course of research, one must ultimately argue for the abolition of IVF as it is currently undertaken.