i think it's kyle's dad. We now know he has a dad and it's someone in the room the night of the dna test. Kyle's dad was in there. I rewatched that episode and found kyle's dad was the only one besides the little lab assiant unaccounted for when the wire for the hospital power was cut. It seems odd that he was missing throughout the episode and everyone else's location was known.
-kyle was making fun of eric for not having a dad at the start of "200"
-kyle has ab- blood type and so does cartman, if you don't know that is a rare blood type
-only cartman could give an organ to kyle when he was sick
i know i'm forgetting someother things but I think he will find out gerald is his dad but then forget it somehow in the end. Any other ideas on this mystery to help me not study for my sociology exam?