"Doctor, the sheer impossibility of that statement leads me to conclude that you are, in fact, trying to pull my leg," Spock said.
Leonard made a rude sounding noise and reached for a hypospray, as was his habit when dealing with overly stubborn patients. It didn't even matter whether or not there was anything in it, holding it made him feel better. "Oh, so you jump right on the time travel wagon at the first sign of trouble but I tell you you're pregnant and suddenly the odds are too long for you?"
"Time travel is improbable, not impossible," Spock replied calmly. "I am male; it is impossible for me to be carrying Lt. Gaila's child."
"And, since she's the one with the ovipositor, it should be impossible for Gaila to be pregnant with Nyota's child. I didn't hear any cries of 'illogical!' from you then."
Leonard loaded up his hypospray with pre-natal vitamins and injected it into Spock's neck. One corner of his eyebrow twitched. "It was also really, really unlikely for Nyota to become pregnant with your baby, what with her tubes being tied and all. And yet, you're all pregnant and I'm in dire need of alcohol. Congratulations."
"Your dependency on mind altering substances does not change the fact that it is impossible for me to be pregnant."
"Yes, you are," Leonard showed him the readout display. "See? There's the uterus that sprung out of nowhere, here's a channel I'm pretty sure will result in a vagina..."
"This is illogical." Spock hissed.
"Well, next time we end up on a trading world with loads and loads of fertility goddesses, maybe you shouldn't have a threesome," Leonard told him, privately agreeing. He wasn't going to let the Vulcan know that, though. "Go talk to the women, I'm going to write up my medical report."