Thank you all. I thought that she was a girl.
Where i live in England we can't have a cat spayed until they are 6 months old. She is kept indoors though so no chance of pregnancy until i can have her spayed.
'He' was sold to us at 9 weeks as a boy. I doubted it from the start as 'he' had no testicles but was tiny so we thought that may have been why.
'He' is now 14 weeks and still missing testicles. I am convinced he is female. My fiance thinks it is a boy. Luckily it has a neutral name.