YOU SAID:

I have a baby sister that has a baby that has a baby

INTO JAPANESE

赤ちゃんのいる赤ちゃんの妹がいます

BACK INTO ENGLISH

I have a baby sister with a baby

INTO JAPANESE

赤ちゃんと妹がいます

BACK INTO ENGLISH

I have a baby and a sister

INTO JAPANESE

赤ちゃんと妹がいます

BACK INTO ENGLISH

I have a baby and a sister