I know what you mean, Twiss XD I call Skinny a he often, even though I don't know for sure yet! Even if Pepper doesn't have them yet, he may within a few months. From what I can tell, most ADFs that are sold in pet stores haven't yet reached maturity. At least, that's been the case with mine. Tubby got his within a month, and Skinny has yet to show any signs of being definite male or female.
Funny thing happened to Skinny tonight... I was feeding them the Zoo Med frog pellets (since my bloodworms are in my other freezer), and Skinny decided to meet my baster halfway up the tank wall. Well... he ended up sinking back to the bottom on his back XD Got stuck that way for a good 5 minutes before he managed to flip himself back over. I would have taken pictures, but I seem to have misplaced my camera. Again.