Just a few days ago, an ex-girlfriend contacted me and informed me that I have a son. I am 35. He is 18. I don't know if he is mine or not but I will find out via paternity test. The reason she contacted me is because he is in end-stage renal failure. Apparently, his mom is not a match and he has some rare tissue type or something, which means I would most likely be a match. I really don't want to give up a kidney and I don't want a relaltionship with the kid. It might have been different if I knew so many years ago. I am also afraid she will now come after me for back child support. Since I am being forced into all of this, I am curious if I might be able to cut a deal. Maybe like donate a kidney in exchange for back (and future) child support. Would this be possible? My other option is to just refuse to donate if I am a match. I want to know what I would be liable for if/when he dies. Would this waive all back child support since he wouldn't be around to benefit from it.