I'm no lawyer, but if this guy's not on the birth certificate in the first place...there's nothing but heresay as to his fatherhood, so I'd say he doesn't need to sign anything.
That's NOT easy - Scorpio is the most private birth sign.
Ask him or if this is about having sex, ask him to show ID or even birth certificate. Sex is illegal to have with a 14yo.
Guy Lux's birth name is Maurice Guy.
Guy Peires's birth name is Guy Peires.
Guy Masterson's birth name is Guy Mastroianni.
Guy Grosso's birth name is Guy Sarrazin.
Buddy Guy's birth name is Guy, George.
Guy Gilles's birth name is Guy Chiche.
Guy Chamberlin's birth name is Berlin Guy Chamberlin.
Guy Lafleur's birth name is Guy Damien Lafleur.
Guy Sebastian's birth name is Guy Theodore Sebastian.