Ok @Bee9908 another try for you, this was from a few questions of yours back in the thread.
- "They are not siblings or cousins. Both are married couples. It is possible for them to get pregnant by “try for baby” interaction, but I cannot add kids in CAS, I can only create a kid of one of my sims."
So, simply click on the + sign not 'play with genetics' all the time, just 'add a sim' - family association afterwards: with the plus sign (on the right of the sims) or adding from gallery and merging is the normal / easy way to add to a family
Sasha
nb: If this solves your question, please mark the reply as having been the solution, so as to help others with a similar problem in the future.
I have no connection to EA
