Ok, I am usually decisive with this kind of thing, but I think I come down on:
Not criminal, but an ethical violation that warrants immediate dismissal.
Basically, a Seattle court has ruled that a teacher cannot be criminally charged for having sex with an 18 year old student. The court states that the state law is "vague" and only intended to stop teachers from having sex with students under 18.
Edwin “Red” Mueller Story Teller Extraordinaire
4 hours ago