Alien Plant Sims spawn human plant babies

Most of my plant babies grow up to be tan humans regardless of how many generations of alien parents they have in their genetics. This only seems to differ if the alien parent came with the game (Johnny and Stella).

Things to note: 

Results are the same with or without various PlantSim mods. I've experimented with generating new plant sims and breeding them both with and without mods and kept sims who might have modded lines away from lines that were produced without the mods to make sure I had clean tests. I originally added the mods to see if I could get different results. In the old days, I used the PlantSim path to more quickly produce alien sims with human eyes.

Screenshot 1:

1. I converted Stella and Johnny to PlantSims, and they consistently have alien plant babies.
2. Stella and Johnny's plant sim offspring often don't have alien offspring. See the screenshot.
3. In the screenshot, one of Stella's plant baby offspring spawned a plant baby when he was still a plant sim (you can see his pointed ears). She was human. After taking plantrophic-C, he had a baby with someone. This baby is alien.

Screenshot 2 (Bradford Pear)

Bradford was spawned by a full alien PlantSim:

1. The top level parent (not shown) was a Servo who became a plant sim.
2. The next level parent is a human plant sim.
3. The third is an adopted alien child who became a plant sim and spawned Bradford Pear (I give all plant babies a plant name)
4. Bradford Pear has fathered a lot of offspring naturally and via cheats. All of his plant sim offspring have been human.
5. When he breeds with an alien, the offspring are alien.

Screenshot 3: (Albrin Cooke)

Albrin was born via alien abduction and became a plant sim. 

1. As a plant sim, all of his plant sim babies are human
2. If he breeds with an alien, the offspring will be alien (the redheaded boy is adopted

Screenshots 4 & 5: (Ageron & Bramble Singles)

1. Ageron was adopted by a PlantSim.
2. Ageron consistently spawns human plantsim babies. ONCE, he spawned an alien plant sim Bramble. 
3. Simulating genetic merger with himself produces humans.