THEY ARE NOT AUTHENTIC, SO DON'T BUY THEM!
Unless you keep a DNA lab at home and have original DNA from Washington, Lincoln etc.to compare your "hair" purchase to, don't buy it. Simple. This is really one of the most obvious scams going, but a very successful one because it is human nature to want to trust the seller and believe what they say. Give the money you want to spend on a minute piece of someone's hair to "Make-A-Wish" and let some poor kid have a fun day while being so sick.