What causes the offspring face distortion in TS2? And how do you fix it?

[Pyromaniac]

So I recently learned about the "offspring face distortion" issue in TS2. Most people have likely experienced this in-game, where sims' faces become more distorted with each generation no matter how non-offensive the parents look. Some folks have tried to figure out why it happens and how to prevent it, but have yet to find a solution, and few people have the coding expertise to dig deeper. You can read more about it here. No matter what facial templates (Maxis or otherwise) were used to make the parents, all offspring born in the game (and created in CAS) will inevitably have some degree of facial distortion, even if they were spawned from parents with identical faces.

Some examples from people on tumblr:

(it seems to be worse for female faces.)

As funny as it is to imagine that these are genetic defects arising from frequent inbreeding and lack of genetic diversity in small hoods, I don't want to be forced to immigrate new sims every few generations just to keep the offspring looking decent. Even if that's the moral of the story.

Any idea what causes this, and how it can be fixed?

[Milhouse Trixibelle Saltfucker III]

Recommended solution: Take OCD meds and find something better to rub off to because the game implements random variation, like in real life. What kind of creep looks at sims' faces that closely anyway? I bet you crane up within two inches of people's noses on the street too. Besides, in your pictures, the kids look just as ugly as the parents. This just seems like something only terrible people care about.

[J. M. Pescado]

It's probably some kind of random drift function to try to ward off sameface, except it's not very random and thus drifts in the same direction every time.

Let me know when you get to Habsburg Jaw.

[Pyromaniac]

That'd be pretty cool if it were actually random. Sadly I'm guessing it's hard-coded into the game, so I have no choice but to get over it keep a few chosen sims attractive by unnaturally prolonging their lives while the neighbourhood gene pool degenerates.

Or it could be a milestone for the hood. First sim to Habsburg becomes mayor of the town.

What kind of creep looks at sims' faces that closely anyway?

The kind who spends close to 50 hours meticulously hand-picking custom content and replacing the default clothing meshes and textures in simPE to their liking. If I were smart enough to take meds for my sickness, I already would have.