Embryonic Stem Cell Research Ethics and Moral Obligations

I was looking up information about stem-cell research. Interesting enough, the most credible looking sites (well, the most sites period!) were very scientific and explained all the reasons why it was a good thing.  When I tried to find ethical arguments for and against, I didn't find as much as I thought I would.  What I found, again, were very scientific explanations about how and why it is done.  They glossed around the ethical portion. 
I found one Times article from 2004 which basically called anyone against it, stupid.  His argument was, that proponents of in-vitro fertilization with implantation of the embryo into the mother could not possibly be against embryonic stem (ES) cell research.  He had a valid point.  Unused fertilized eggs (embryos) are often discarded unless they are donated for research.  So what is the difference between "throwing them away" and "using them for research"? 
     The argument against ES cell research in general is that it is using "fertilized" eggs.  If your view is (as mine is) that human life begins at conception and is worthy of all rights of any human being, they you cannot advocate research on embryos any more than you could aborted fetuses or full term babies.
     My original question was why, with in-vitro fertilization and implantation, do you have to fertilize more eggs than you are going to implant, thus the need for discarding unused ones?  The reasoning is understandable.  They (doctors, lab personnel) do not know which eggs will become viable.  If they only fertilized 3 at a time, with a large percentage rate of failure expected, they may be wasting a lot of valuable time for the mother.  At least, that's my limited knowledge on the subject surmising.  So, the idea is to be more efficient and cost effective.  Fertilize a bunch, hope a few "take", implant those that do (another question of ethics implanting 7 embryos vs. only 2 or even 3), and pray that at least one will become the baby the parents are hoping for. 
     I think it comes down to those odds, and cost effectiveness, and time that drives the dilemma.  What if you could fertilize 2 at a time, implant them if they became viable, and retry if they didn't?  Cost... Time....  So, perhaps THAT should be our discussion.
     The author the Times article stated at the end than UNLESS you were an absolutist (aka. fanatic) you needed to "get out of the way" of ES cell research.  At least he gave me a leg to stand on. I'm one of those fanatics!