Question: Is it true that male cats cannot be calico and female cats cannot be orange tabbies? Answer: Not true in either case. However male calicos are uncommon: Only one out of every 3,000 calico cats is male, inning accordance with a study by the College of Veterinary Medicine at the University of Missouri.
The gene that governs how the orange color in cats display screens is on the X chromosome. Any cat, male or female, can be orange, however in males the color is nearly constantly expressed in the tabby (striped) pattern, in some cases called a ginger tom. Females can be orange tabby, calico or tortoiseshell. (The last two are genetically similar, other than the calico has spots of white, orange and brown or black, and the tortie’s colors are orange and brown or black swirled together.)
Since the orange is divided among tabbies, torties or calicoes in women, there are fewer of each type. And since orange is usually related to tabby in males, it appears as if there are more orange males than orange females. That’s probably the case, but nobody’s counting.
Here’s where it actually gets interesting. Female cats have two X chromosomes, while male cats have an X and a Y chromosome. For a cat to be a calico or tortoiseshell, the animal should have two X chromosomes, which indicates the cat is going to be female the vast bulk of the time. When the calico pattern exists in a male, it’s since the cat has three sex chromosomes: two X, one Y (male).
The XXY mix is a hereditary rarity that sometimes appears in cats (people, too). And if both X chromosomes carry the calico blueprint, you’re taking a look at one unusual cat: a male calico.
Such XXY animals are called Klinefelter males, after the doctor who first explained the condition. If you have a male calico and believe you can generate income breeding him, you probably will not. Though lovely, the cats are normally sterilized.