Unlike other animated shows like The Simpsons, the characters in King of the Hillactually age and the episodes are continuous from theprevious one. Bart, Lisa, and Maggie Simpson have stayed the exact same age for 20 years or sowhile Joseph Gribble hit puberty in the 5th season. I would hope the writers of the show would at least start drawing Bobby to look more mature. It's been 12 seasons, people! But, I have now thought of a possible way they could get away with aging Bobby like they did Joseph:
They could have an episode where Bobby finally matures like Hank has always wanted him to. Bobby's 14th birthday is approaching and he still has no signs of physical maturity. Hank brings Bobby to a doctor and they doctor reveals that the cause is that Bobby has low testosterone levels. The doctor tells Hank they could help speed up the process of Bobby's puberty. Hank is hesitant at first, but when he sees how immature he is and how Peggy treats him like a baby, he's like, "That's it. He's getting the operation." The doctor gives Bobby the operation over a period of months and the effects start to appear. Bobby gradually starts to grow taller, his voice deepens, and he starts to grow a little facial hair on his upper lip. Hank even seems to notice that he has built a small portion of muscle and can actuallylift some weighs. The episode could have the simple title "Bobby Hits Puberty". Maybe it could end with Bobby finally acting like a man, standing with Hank and his buddies and drinking beer with his new moustache on his facein front of the fence. When they reach him doing their usulal mutterings, he goes, "Oh yeah!".