Have to get rid of my cat.

My cat stays in my room, always had. But my little sister had a baby and now all of a sudden i have to get rid of him?? That has NOTHING to do with me and my cant. “The cat is gonna steal the babies breath” “cats jump on everything “ WHAT DOES MY ANIMAL THAT I LOVE HAVE TO DO WITH SOMEONE ELSE?!? MY step dad is trying to say he can get them leashes and flea collars so they can sit outside…they arent dogs dogs dont even need to sit outside all the time. I dont know what to do and i shouldn’t have to get rid of my animals because of someone else.