The were genetically engendered yes, but they were made to bread true.

If the sealing of the DO was somehow going to stop their bodies from working, then they would of just up and dropped dead insistently, much like how the blight itself was vanishing right before their eyes.

Now we only saw less then a day post LB, but nothing we did see showed the shadowspawn up and dieing.... Which could very easily become a REALLY big problem for WoT earth.

Just imagine, they actually win the Last Battle, only for the shadowspawn, now free from whatever hold the blight had on them, spread across the world...

So long as "The Shadow" loses it's hold on them now that the DO is sealed(as in their no longer always pure evil), it actually sounds like fun.

Actually kind of hope that's what happens, as not only does it give the fourth agers a little to do, but it's also nice to think that there's hope for those poor souls unlucky enough to be reborn as shadowspawn.