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
You should move to Japan!