I've read the other answers and agree that KC mentioned sexual advances (by her father or Lee?) to JG. JG said he didn't ask many questions because the topic was too uncomfortable for him.
TL said that KC had talked to him about this subject also. I don't recall the friends mentioning the subject.
For some reason this topic is very taboo around here. LE tested Lee for paternity of Caylee and outruled him as the sperm donor. I would have liked, in the interest of being thorough, to see another test performed on another male family member but that's just my suspicious mind working overtime. KC also has several male cousins.
The over the top family dynamics, jealousy surrounding Caylee, ownership issues surrounding Caylee, multiple changing stories about who Caylee's bio was, the denial and weirdness of CA hiding KC's pregnancy for so long even though she was carrying a baby that was obvious to other people, the fact that GA says he was soooo happy to be a Grandpa but moved out right after he became one - all these factors keep me wondering :waitasec: and wanting the true answer as to who the real bio was. Incest can really mess a girl up. Ironically, there is a famous person talking about this very subject in the news currently.
Finally, KC tried to pass Jesse off as Caylee's bio. That is a dishonest act that has only brought JG pain in the long run. I can't blame JG for being angry for being targeted by the A family - they have some nerve.