Newt and Porpetina Goldstein had a son who in turn had a son named Rolf... Luna Lovegood would eventually marry Rolf Scamander, and thus Newt became her grandfather-in-law. I did not yet find any info about the question if the two ever met. Luna would however, after graduating from Hogwarts become a magizoologolist, just like her grandfather-in-law, and just like her husband. Luna has two sons with Rolf Scamander. Lorcan and Lysander.
