[He can't help enjoying the look on Sam's face, especially since it's currently Chuck's face, and she's so good at such looks!]
Relax. It was a very long time ago, and it wasn't natural. I played host to an alien. It lasted nine days and I was hell to live with the whole time.
((OOC: Totally canon. At least, Jack has a line, "At least I won't get pregnant. Never doing that again!" and once can extrapolate whatever one likes from that! *g*))