Where do stem cells really come from?

I'll just get this out of the way: I consider myself "pro-life," but not because of religion or faith; I'm agnostic, and don't believe in either God or gods. I don't believe that zygotes are human beings (but that doesn't mean they're not human, if that makes sense). Abortion should be legal, and is even desirable in some circumstances. I would not repeal Roe v. Wade. However, the idea of nonchalantly accepting embryos as a resource for research concerns me.

I'm trying to find some neutral, well-documented facts on how stem cells are obtained, preferably a resource that indicates proportions/percentages. I wouldn't be surprised if the majority came from fertility clinics, not from aborted fetuses. However, I find it a bit difficult to believe that states that allow abortion wouldn't also allow aborted fetuses to be harvested for stem cell research.

Does anyone happen to have a resource that isn't put out by frothing fundamentalists or vitriolic pro-choicers? Thanks in advance.

We already have a variety of ways to generate stem cells for therapy without the use of embryos.

Here are some articles that might change your perspective:

http://www.cell.com/cell-stem-cell/abstract/S1934-5909%2807%2900330-X

http://www.nature.com/stemcells/2008/0810/081030/full/stemcells.2008.142.html

inb4 this thread breaks down into religion based debacle that Tegumi locks.

Stem-cells dont have to be embryonic. Adult stem cells can turn up in bone marrow and a bunch of other places it seems.

University of Wisconsin has an entire stem cell research center. They do refer to the "ethics" part of it but they dont take a position other than "well a poll says people support it so let us work in peace". I hope this isnt super pro-choice or something, I dont follow abortion closely.

This document from that site says they get them as leftovers from IVF's. I couldnt find anywhere that said "40% from IVF's 30% from clinics, etc"

I have also herd some stem cells could come from the placenta or the embryo. Is that true? (cause if it is this really reminds me of bioshock)

Short answer: yes.

In fact there's a practice nowadays to freeze some of the blood from the umbilical cord, as the stem cells in it are genetically indentical with the child and later on in their life may come very handy.

Most embryonic stem cells come from blastospheres that were discarded by in-vitro fertilization procedures. I'm not aware of anyone that harvests hESC from aborted fetuses.

Adult stem cells do exist, but they're less effective because of telomere reduction and (usually) more mutation. There is some research being done in reverse engineering pluripotent cells into stem (totipotent) cells.

In the USA (where I'm most familiar with), the NIH has most of the guidelines posted at the relevant resource page here.

As of 2009, it is now legal (in the USA) to create embryos for research, using donated materials. Properly speaking, since they are harvested in the 8- or 16-cell stage, they aren't "fetuses", but rather "embryos".

...you can find them even in an umbilical cord.

It's not all about "derp kill the babies" that religious fanatics would have some beleive.

My belated thanks for the responses and for the links. It's appreciated!