This is not the first time this has happened to me with bottle-fed kittens. Believe me, I leave it to the experts because their private parts are so little when they are really young, that I can't tell at all. Obviously it can be tough for even the expert to tell sometimes.
So, Ms.Tugboat already has a new home next week after the spay procedure, so I am going to let her new family decide a girl name (or not). I will always think of her as Tugboat, or Tug for short. So now, lets see if I can remember to refer to her and a "she."