If your Sims had a love-child with the Grim Reaper, we he eventually have to reap the soul of his son or daughter? Or would he make the choice to keep the Sim alive forever? That's some high drama if I ever heard it!
Technically you could with mastercontroller's assign role. They patched out the black skin for reaper babies, but it's still possible with wooher and simbot babies.
This is how Reaper kids come out now:
The simbot kid is in the top of the picture. Sorry I can't open the save anymore.