I've had a couple of kittens in in the past who have been wobbly on their legs and brain damaged. Shelby I still have but did improve drastically to how she was when I first got her in. The vet thinks with her she had some meningitus type bug which has left her brain damaged, also other instances are if a kitten has a liver shunt, I had one last year, he kept going wobbly but he was having seizures as well. He did have a shunt but sadly before he had the results back, I had to have him put to sleep. Another I've got in at the moment although an adult cat has an inner ear infection. She was admitted to the vets for a few days and is still quite wobbly and falls over, it could be a number of things and you won't know until he/she's been seen by a vet. A lot of illnesses have similar symptoms but can be totally unrelated, also it could be a birth defect, possibly trauma at birth. I would get her checked by a vet and take it from there. Good luck and keep us posted, xxx