Billy, the Mystery Cat

It's a bit of a tale. Billy was born on 6th June 2013, the last and smallest of Biscuit's five kittens. Today I took her to the vet as she is seven months old, starting to get frisky. We thought she'd make a lovely mother so it was a hard decision to have her spayed, but there are a lot of cats in the world.
The vet weighed her and inspected her teeth and eyes and said..." I'd better just check, before the operation..." and lifting her tail, he paused and continued, ..."oh, actually, Billy is a boy!"
It doesn't seem to have made a lot of difference to Billy. But it's made us all laugh and think about how one constructs apparent "facts" on quite limited evidence. How little we know for sure. Meanwhile Billy the mystery cat purrs and licks his paws.