King of the Hill is a fairly realistic show that doesn't seem to keep any secrets hidden from the public's eye. Or does it?

Hank is NOT Bobby's Real Father

This theory questions Hank's validity as Bobby's biological father, because there was an episode that explained that Hank had a narrow urethra, and thus wouldn't have been able to conceive his son, Bobby, with his wife, Peggy. According to the theory, Bobby's real father was actually Bill all along. This theory is supported by the fact that Bobby looked more like his neighbor, Bill(Both overweight, shorter than most people, and have large appetites), than his father, Hank. This theory also suggested that, prior to Peggy's marriage to her fiance, Hank, Peggy had relations with an unnamed man, and that the episode that followed was really just a lie that was subtley trying to hide the truth from the audience. This theory also explains the extent of Bill's crush on Peggy, and it also explains her distaste towards him. It's also believed that this theory is confirmed in the series because of all the moments in the series in which Bill had a father-son bonding moment with Bobby, and that, unlike with the case surrounding Dale's son, everyone, except for Hank, know Bill's dirty little secret. It is also possible that Peggy had a relationship with Hank's father, Cotton, since he resembles an older version of Bobby, which also explains his soft spot for him. The reason why Peggy dislikes Cotton is possibly because he sexually abused her and his racism, ending their relation. Though, it is possible that Peggy and Cotton did not have a relationship.