We recently moved to a new place with our two 4 year old cats, 1 male (neutered) and 1 femaile (spayed). There are several feral cats that we have decided to feed outside of our home, one of which was obviously pregnant. When she had her 5 kittens, we took in 2 of them at about 4 weeks old. They are now 8 weeks old and I think I can tell that one is female and the other male, but my son does not believe me....Isn't it obvious by now what sex a kitten is?