If you turned down 21K then you definitely must have thought it would be worth more some day. I will make the assumption that you paid $8 for this. At some point you have to cash in when you get a crazy offer.
I believe your story, but I suggest writing this off as a costly lesson. I am not so sure you could get more than a few hundred for this, if that. Yes, I could be wrong, but each minute you spend on this just adds to the pain. I think you have a better chance of seeing God than you do of ever making peace with this name.
This name isn't so much more than a reg fee name to me, though I am fairly certain that those who are into the stem cell issue and have sites could be potential buyers in the low XXX range (you will have to do lots of legwork or get really lucky). My guess is that if you put it up for sale here you wouldn't get $100 for it.
You are going to have to work pretty hard to unload this, as I am sure it doesn't get much traffic or make money. There are stem cell related stocks that used to be high-fliers that crashed to earth, and I am afraid this name has suffered a similar fate. If that 21K offer was real, then those people were close to insane, and I bet they are now bankrupt.