Understanding Color Genetics of a White Cat

In order to produce a white kitten, at least one parent must be white. The gene that produces the white coat is a dominant masking gene which merely serves to "cover up" the true color. 

When breeding, the color that is masked by the dominant white gene may surface, producing offspring with color.  Basically, any color or colors may be masked by the gene. When breeding a white cat, it may take multiple litters to determine the color that is being masked by the white color. However, if a white cat carries the homozygous chromosome, all of their offspring will be white. The definition of homozygous is the possession of two identical forms of a particular gene, one of which is inherited from each parent.

Quite often, white kittens are born with a smudge of black, red or gray hairs on the top of their head.  This is due to the varying masking ability of the dominant white gene.  The spot disappears as the adult coat starts to grow in at about nine months of age. 

Eye Color and the White Cat

How is eye color described on a white cat?  Breeders will refer to the eye color of a white when describing a cat or kitten. For example, they may use the term or abbreviation CEW, meaning copper eyed white.  The abbreviation or term OEW, meaning odd eyed white.  An odd eyed white would be a cat with one copper and one blue eye.  The term or abbreviation BEW, meaning blue eyed white. 

Deafness and the White Cat

Are all white cats deaf?   There is an old wives tail that rumors all blue eyed white cats are deaf.  Howevver, not all white cats with blue eyes are deaf. Unfortunately, there is no treatment for hereditary deafness in cats.