Ross was a professor in the later seasons. In the early seasons, he’s a highly paid researcher. They even did a whole episode around how successful Monica, Chandler and Ross were…
By showing the rest of the gang unable to afford Hootie and the Blowfish tickets.
Freddie’s mother appears quite frequently. I don’t know about his father, but with as psychotic as she is, my guess is that he divorced her / ran away.
Sam’s mom hasn’t been shown on-screen, but has been hinted at being a rather white-trash, sleep-around type (as much as that can be suggested on Nickelodeon). And her twin sister is Sam’s polar opposite: clean, polite, smart, attends a private school on a scholarship.
Well, SpongeBob isn’t a child, even though he acts it at times. His parents do show up from time to time.
Another fantasy story: “Pokemon” (all its incarnations)
A 10-year-old travels the world with a late-teen/early-20s man and various scantily-clad young girls. He has several pet pokemon, whom he regularly has fight others’ pet pokemons. No blood is shown, but it’s often implied that they’re injured, some to the point that they have to go to a hospital (staffed with clone nurses).
Didn’t Michael Vick get in trouble for this sort of thing (animal fighting, that is)?