All cats are born with blue eyes. Their adult eye color will begin to appear in 3 to 12 weeks. As a result, eye color is not recorded on CFA registration records except in the case of white cats. White cats whose eyes remain blue have a high chance of deafness. Those with only one blue eye will likely be deaf only in the ear closest to their blue eye.
Although it is a matter of some contention, there are approximately 70 breeds of domestic cat recognized by at least one major cat registry. The IPCBA (International Progressive Cat Breeders Alliance) recognizes 73 feline breeds, while the CFF (Cat Fanciers' Federation) recognizes only 32. The CFA (Cat Fanciers' Association) strikes a middle ground, recognizing a total of 41 breeds. At the center of this controversy are breeds such as the Savannah or the Bengal which the more conservative registries refuse to recognize because they were bred from "wild stock".
Siamese cats are sometimes cross-eyed due to the abnormal uncrossed wiring of their optic chiasm, the part of the brain where the optic nerves partially cross, with those parts of the right eye which see things on the right side connecting to the left side of the brain and vice versa. In some Siamese cats, this wiring is disrupted because there is not enough nerve crossing. In order to compensate for the lack of this connection in their brains, cats with this defect will cross their eyes. Albino tigers sometimes suffer from a similar condition.
If a male cat is both orange and black, he is probably sterile. Both of these colors are carried on the female X chromosome that cats receive from their mother. Normal male cats only carry one X chromosome, so they can be orange or black, but not both. Under extremely rare circumstances however (1/3000), a male cat is born with an extra X chromosome (XXY), in which case it is possible for him to be both black and orange. This unusual combination of chromosomes, however, will almost certainly render the male cat sterile.