I really liked the Weissmuller Tarzan movies when I was a kid. Watched a lot of other renditions, but for me Johnny Weissmuller was the best Tarzan, while Maureen O'Sullivan was the best Jane.
As I remember, Boy was not their real son. They found him alive from a plane wreckage maybe. I think boy's real parents were supposed to be relatives of Jane or Tarzan. In the books their family names were Clayton and Greystoke. I know I read that censors at that time would not allow Tarzan and Jane to have a baby, as they were not legally married.
The movie in which Boy was introduced was " Tarzan Finds a Son " or " Tarzan Takes a Son. " I know it was one of my favorites.
In the books, " Son of Tarzan ' was like the 4th novel and introduced Korak, later to be known as Korak the Killer. Korak was really Jane and Tarzan's son. Korak was his "ape" name, but I don't remember the name Jane gave him.
The first few of the novels are really good and I would recommend them to you highly Stunt. Edgar Rice Burroughs had Tarzan learn how to read English on his own, and was later taught how to speak it perfectly by a Foreign Legion soldier and Jane. I watched a show that said Burroughs went to a premier of one of Weissmuller's films, and walked out in disgust at the " Me Tarzan, you Jane " kind of speech by the movie Tarzan.
I really liked the films though, even if they weren't perfectly true to Burrough's novels.