#nudefatherandson (?)
As with #nudemotheranddaughter I don’t have proof that these really are fathers and sons other than the caption said they are and looking at age difference, familial similarities and body language.
Before the USA sank into obnoxious pruderies and unchristian values promoted as gospel truth, in short when people still had common-sense and interacted with reality instead of social media - the YMCA hosted naked swim lessons (1950s and 1960s, and earlier). Men were not taught to be afraid of their body.