Forensic Science
There's a man standing in the middle of a room. "Ah, at last you have come. I have been waiting so long for this to happen." he cries. You stare at him confused thinking that he has gone mad. "You think I have gone mad? Yes? I will show you what I'm talking about." He walks away and beckons you to come closer you walk over to him and you see on the metal device is... your son! "This is your son?" you nod in agreement "Well I have a proposition to make to you, I will give you the cure for your son and in return, you will give me some of your sons DNA." What do you say back?