Okay, I know from what I have read that The Jetsons theme was thrown together in a hurry, but why “His ‘boy’ Elroy”?Why not use the word “son” there? They did for “daughter” Judy.
Was it for the sake of the rhyme? I don’t remember the whole damn thing, but I believe Elroy and “boy” were the only words that did rhyme.
Okay, Jetsons fans! Set me straight here! 
Q
What’s the question? It’s not like its some incredibly strange turn of phrase. “Boy” is a perfectly common synonym for “son.”
It sounds better. Would you rather it be “His offspring of the male gendered persuesion who has been bestowed the noble designation of Elroy”?
I told you guys I was nitpicking. I also told you of reading that the theme was hastily thrown together. Just sounded to me like someone missed something, that’s all. Cool your jets (:D)! It ain’t that big a deal.
Quasi
But why stop there? Why is he named “Elroy” at all? Why not “Elvin” or “Elwood?” We demand the truth! (Where’s Oliver Stone when you need him?)
Because none of those rhyme with “boy.”
:: singing ::
“His son, Elson…” 
Zev Steinhardt
:: singing ::
“His lad, Sinbad…”
H.
Maybe Elroy was referred to as his “boy” rather than his “son” because he was considerably younger than his daughter, Judy.
::singing::
"His tot,
…uhm…shit…
oh! Lancelot…"
His “part” Steinhardt!
Yeah I know: That was a reach, but I couldn’t resist.
How about “His failed Rubba…Bubba!”
Q
“His kid, El Cid.”
“His rug-monkey, Spunky.”
“His tyke, Thorndyke…”
Doesn’t Cid rhyme with seed?
It does on The Tick. 
how do we know Elroy is really his son and not the result of an affair between Mrs jetson and Mr Sprocket, hmmmm?
“His twerp, Anthwerp”
It’s better than “His son Elron”.
:: singing ::
His offspring, Irving!
I didn’t read the title closely, so I thought this was going to be a complaint about the “his” (rather than “their”, chauvinistically ignoring Elroy’s mother, Jane).