I FIGURED IT OUT!!!!!
I'd been having this problem for HOURS now. I tried everything, and was really worried I'd have to delete this (long-running) household of mine, but the Harrenses have been saved!
Here's what you need to do (In my case there's more than one member in the household and I had deleted the pregnancy moodlet - which you do with 'testingcheatsenabled true' and then ctrl+click the 'Baby Incoming!' moodlet[this is considered a mistake by many]):
On the Cheats Window: type "moveobjects on" (without the quotation marks), and hit enter.
Change to Buy mode (Make sure the Sim is at 'Home' or the Community Center in "Into the Future")
Click on the Sim to have it selecte3d.
Hit Delete.
Yes, your Sim is now gone! Don't despair, though.
Now, with the remaining Sims, travel back to the Past (or, possibly, the Future if you're in the present with these problems).
After the loading window, your family should be back in whole. (In my case the Sim appeared at the Home lot, then disappeared and was spat out by the Time Portal after everyone else was already standing.)
Yes, this may seem drastic, and no, it hasn't been tested multiple times. However, if you're at the point where you think deleting the family may be your only chance, try this! It may well work for you, too!
Happy Simming!
