Female orange tabby cats aren't uncommon; approximately 20 percent of orange tabby cats are female. In the cat, the gene for the orange color is located on the X chromosome and is recessive. Males only have to inherit one orange gene to appear orange, while females have to inherit two.
When two orange tabbies breed, all of their offspring, male or female, are orange tabbies. Females that carry the orange gene on only one X chromosome are tortoiseshell in color. Only one out of 3,000 tortoiseshell cats is male. These males are almost always sterile and are found to carry an extra X chromosome.