Help!!

I have 6 sims living together in one house. (2 females, 2 males, a baby boy & a baby girl). Sim 3 & 4 are married & I just moved them in because I needed to make space for new sims. Sim 1 & Sim 2 are married & are the original sims who lived there & both kids are theirs. Sim 1 went through the pregnancy & everything with the baby boy. When the baby was born, however, she didn’t get titled as his mom & neither did the dad. Sim 3 & 4 got the title of mom & dad when they arent even the parents. How can I change that? Do I have to kill the baby or something? It is so frustrating, I moved Sim 3 & Sim 4 out to see if it would change anything & it didn’t. Please help. 😭😭