Baby genetics are really buggy. Has to do that babies literally only have four human skin tones. Alien babies thankfully have less issues with genetics now than they use to and the sounds they make are adorable so why I prefer playing with them. Why babies being changed to life stage would help a lot because of how frequent the genetics glitch on them. Bug has been occurring since 2014 so since the game came out.
I know this bug isn't always mod related but the invisible crib mod seems to cause it with this report.
https://answers.ea.com/t5/Technical-Issues-PC/baby-skin-colour-change/td-p/9835233
I found this thread too:
https://answers.ea.com/t5/Bug-Reports/OPEN-For-Some-skin-tones-Baby-icon-different-color-than-Sim/m-p/10379126
