YOU SAID:
is the son of my son also my grandchild?
INTO JAPANESE
私の息子の息子は私の孫でもありますか?
BACK INTO ENGLISH
Is my son's son also my grandson?
INTO JAPANESE
私の息子の息子は私の孫でもありますか?
BACK INTO ENGLISH
Is my son's son also my grandson?
That didn't even make that much sense in English.