"Not as far as I know." Sam shrugged. "I can change at any time, so it stands to reason that I should be able to bite someone at any time. I mean, it's not a decision you have to make right away or anything - it could be years. I just...I figured I'd kept it a secret from you long enough."

And he probably wouldn't have been able to keep it secret much longer, anyway. Trying to hide his disappearance at the full moon was always difficult.

He breathed in slowly, then exhaled. "If we could keep it a secret, then I'm willing to let Tony study whatever he can. If you agree, I don't want something going wrong that we could have prevented, you know? I just don't know how much science is gonna be able to figure out."