"Ray_Trace;c-18187985" wrote:
I also have a sibling Sim who is able to romantically flirt with her brother, but that's also because I added her relationship via MC Command Center and hadn't generated it through CAS. The Sims I had made siblings through CAS, I couldn't do romantic socials with them.
I created her siblings via "play with genetics" in CAS but that seemed to mess up the family tree so in the end i added the relationships with MCCC. I added her two siblings to her household and using cas.fulleditmode i can only choose "household member" or "fiancée" under household relationships.