Mrs. Rodent has volunteered us to look after her friend's cats, and showed up last night with a mewling box of fur under each arm.
"Awww, aren't they cute!" I said, "Are they boys or girls?".
"One's a boy, one's a girl" Mrs. Rodent responded, to my surprise.
"What, have they been neutered?".
And, in tones of ultimate weariness as if addressing a slow child, Mrs. Rodent said "They're brother and sister."
Well, that's okay then. I'm listening for the pitter-patter of tiny paws.
It doesn't quite beat the worst incident of girlfriend daffiness I've ever heard - the guy who was puzzled to learn that his girlfriend believed that Tony the Tiger from the Frosties adverts was female.
It took a moment for the explanation to come out - "Lions are boys, tigers are girls!".
But it's surely up there.