Posted in here before, with a longer winded rant about the genetics.
A lot of my Sims are first generation, and pretty low-key on how I made them. Like I would have a spell caster, with red hair and blue eyes, and their partner would have blonde hair and green eyes, and also be a spell caster. Another thing is that most of my Sims are loyal to their partner, and I have yet to have any scenarios where they aren't loyal. When I create them, I also will make sure they are withing the same skin tones, like warm, cool or neutral to keep the skin tones from coming out bizarre.
So, with all that planned, and placed, I have still had some strange genetic glitches, not super extreme, but noticeable. For example, one of my couples had a kid, most of their kids followed the eye color of one parent, but one kid ended up getting grey/gray colored eyes, when one parent had blue, and the other one had green. I had to go into CAS, and fix it.
