They're not going to draw blood, they're just going to ask them questions. I'm betting the questions will include things like "Do your parents ever spank you?", "Do your parents use drugs?", and "Are there any guns in your house?".
And you might want to check the sear pin in that mouse button.
So would these answers be used agains the parents in a court of law? In other workds, are we asking the youth of America to rat on their parents?