They strike up a conversation and quickly discover that they're both doctors.

After about an hour, the man says to the woman, "Hey, how about we sleep together tonight? No strings attached. It'll just be one night of fun."

The woman agrees. So they go back to her place. She goes into the bathroom and starts scrubbing up like she's about to go into the operating room.

She scrubs for a good 10-20 minutes. Finally, she goes into the bedroom and they have sex for an hour or so. Afterwards, the man says to the woman, "You're a surgeon, aren't you?"

"Yeah, how did you know?"

"I could tell by the way you scrubbed up before we started."

"Oh, that makes sense," says the woman.

"You're an anesthesiologist, aren't you?"

"Yeah," says the man, a bit taken aback.

"How did you know?"