No. Sean Penn's father was the late Leo Penn, who was blacklisted in the 1950's and ended up directing a great deal of television shows.
Arthur Penn's son is Matthew Penn, who executive produced...
No they don't seem to be, unless they are brothers : Leo is born 08.1921, and Arthur 09.22. in Philadelphia. Leo is the father of Sean & Chris & Michael Penn. He was blacklisted during...