"it's only the potential"
So are you implying that potential shouldn't be given a chance? Sounds rather inhumane to me.
"so harnessing that potential for the benefit of living people is not a crime"
Eye of the beholder. Where's the line? Why not sacrafice a living full grown person? I'm sure a lot could be learned. The debate is about where the line is.
All that said, I'm not really on either side. I can definitely see points to both sides of the argument. I really liked hearing that couples who are trying to have a baby can donate the extra embryos to this research. That IS FABULOUS as they would've been wasted in the past.
The other argument that seems to come up is that if there other ways we can move forward without killing embryos, then why not do that? The argument against it is that it moves much slower. My answer to that is, yah, so? People are born and die everyday. It's a process that's being going on...well, for a VERY long time. What's the rush? And I'm sure the answer to that is, "My friend/parent/child/spouse is dying of xxx" is why it needs to go faster. I understand that. It all just comes down to that question of is it right to end one life to replace another? Is it a black and white issue? Nope.