I feel your frustration. I made a sim I intended to be a mermaid but only saw that as an option for creating a second sim for that household, so I had to start over with her there (I hadn’t worked on her too long). Then I wanted her to have twin human boys and I kept rolling mermen using her genetics and an unknown sim to create a son. Maybe I didn’t roll enough times but I got impatient. So I created a human for her to combine DNA with, then finally rolled some humans. Then I felt kinda bad deleting their father, but ya know, I wanted a small family.