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An orange and white cat laying on a deck to represent cat colors and gender

Genetics On Cat Colors And Gender: Are Calico Cats Always Female?

You've seen them around the neighborhood—slinky calicos with their tortoiseshell markings. Did you know this unique combination of colors is rooted in genetics? It's time to wear your lab coat and understand what genetics means for cat colors and gender.

We'll explore the genetic science behind why cats have different coat colors and whether or not it affects their gender. We'll also touch on exciting side notes and potential behavioral differences between male and female cats. Read on to learn more about cats' genetics!

Basics Of Genetics

Let's start with the basics of genetics. We all know that humans and animals are born with certain traits passed down from our parents. This is because these traits are coded in our genes. When it comes to cats, their gender and coat color can both be determined by their genes.

For cats, one gene determines their sex or gender—so if two X chromosomes are found, the cat is female; if an X chromosome is present along with a Y chromosome, the cat is male. Another gene carries the instructions for coat color—it codes for the cats' fur to be black or orange (or both).

But while this gene helps determine a kitten's coat color at birth, environmental changes can cause it to change as they age. So when it comes to cats, genetics provides some answers—but not all of them!

Chromosomes And Gender Determination

Do you know that a cat's chromosomes determine its gender? Well, it's true!

Female cats have two X chromosomes and are designated as XX. In contrast, male cats have one X and one Y chromosome, which makes them XY. The cat's parents must contribute an X chromosome to be a female cat.

In the case of male cats, one parent must contribute an X chromosome while the other must contribute a separate Y chromosome. Suppose the father passes on two identical sex chromosomes (one being an X). The offspring will likely be a female cat because you cannot get two similar sex chromosomes in a single organism.

The information from these chromosomes determines what coat color pattern and gender is expressed through their offspring. So, when it comes to calico cats (cats with three colors - black, white, and orange), they can either be male or female. It all comes down to how they inherit the dominant genes from their parents!

Why Orange Cats Are Usually Male 

An orange male cat sitting on a wooden table

Any cat person can tell you that orange cats are usually male and tortoiseshell or calico cats are typically female—the reason is simple.

All variations of cat colors are either red-based or black-based. The red color is sex-linked because it is carried on the X chromosome. A male (XY) has one X chromosome, so if he takes a red gene, he will be red.

Females (XX) would need two red genes to be red, which rarely happens. If a female has one red and one black, the tortoiseshell (black and orange) coloring will result. Calico is black and orange mixed with white.

Effects Of DNA On Coat Color In Cats

Conversely, all-black coloring is more common in males than females because males only need one gene to be black, while females need two. Females that are either all red or all black are uncommon, but they do exist. Even rarer is a tortoiseshell male (usually sterile) because he will have an extra X chromosome.

Hair length is also controlled by genetics. The gene for short hair is dominant, and the gene for long hair is recessive. Short hair is more common in cats because it will be dominant even when carried by just one member of a chromosome pair. Long hair only occurs when both members of a chromosome pair have the gene.

What about the supposed connection between white fur, blue eyes, and deafness in cats? This is true in some cases. There are three genetic causes of white coloring in cats: albino white, dominant white, and white spotting.

White spotting produces those familiar "tuxedo" white socks and bib markings. White spotting can also occur on all-white cats. This white spotting causes blue eyes (or one blue eye) and deafness.

If the white spotting spreads to the eyes, they will be blue. If it spreads to the ears (or one ear), it will cause degeneration of the inner ear (cochlea) shortly after birth, resulting in deafness.

Exploring The Rarity Of Calico Cats

A rare calico cat laying down on a piece of cat furniture

Have you ever wondered why calico cats are so rare? The answer lies in genetics.

A genetic quirk creates a calico cat's fur pattern: the cat has three different color-producing genes, which can give the cat an 'orange-black-white' coloration. Because these three genes interact with each other, it can be tricky to achieve the right balance resulting in that unique coat pattern.

Calico Cats Need Two X Chromosomes

The real trick is that two of those colored genes (orange and black) are on the X chromosome. This means two X chromosomes are required to get the calico coloring – and we all know cats have two sex chromosomes, an X and a Y. So female cats (XX) are far more likely to be calico than male cats (XY). It's estimated that almost all calico cats are female, making them rarer than their male counterparts!

This explains why you'll rarely see a male calico cat – but there is a chance for them to exist too! A rare genetic mutation called Klinefelter Syndrome can cause XXY in males, leading to male calicos being born (although this is extremely rare!).

Even though creating a calico cat is a genetic rarity, it's worth treasuring when you find one!

Are Calico Cats Always Female?

Did you know that calico cats are almost always female? Well, it turns out this has something to do with genetics too!

The gene responsible for the female's two X chromosomes creates the black or orange patches on the coat of calico cats; you can only find this gene in the female's X chromosome. That's why calicos are usually female—it takes two X chromosomes (which are only present in females) to make those patches of colors appear.

Read Next: Tips On Caring For Your Senior Cat

For a calico cat to be male, it would have to have an extra X chromosome—an XXY combination instead of the usual XY combination. This is rare and would be fantastic if you ever encountered one!


You may have questions about cats and their genes, which is understandable! Let's review some of the people's most common questions about genetics, cat colors, and gender.

Why are calicos considered lucky?

Calico cats are considered lucky because of their rarity. You've probably already seen a waving cat ceramic figurine displayed in shops or restaurants. This is known as Maneki-neko and is based on a calico cat.

How rare is a male calico?

While getting a male calico is not impossible, it's extremely rare—only 1 in every 3,000 calicos is male. If you ever get a male calico cat, success in breeding them is unlikely as they are generally sterile.

Does the color of a cat affect its personality?

A recent study suggests orange cats are the friendliest, while gray cats are shy or aloof. However, it's important to note that your cat's personality is mainly influenced by its environment and daily social interactions.

Can cats with different colored eyes be both genders?

A white cat with different colored eyes

Yes! Cats with different colored eyes (heterochromia) can be either male or female, as this genetic trait isn't linked to any particular sex chromosome. This can occur for several reasons – from injury to melanin pigmentation problems – but it has nothing to do with the cat's gender.

Is calico a cat breed?

No, calico is not a cat breed. It refers to a tri-color coat pattern you can find on any domestic cat.

Congratulations, you just passed Cat Genetics 101! Good job!

All in all, the relationship between genetics and cat colors and gender is a fascinating one, and it's clear that there's still more to learn.

Even though calico cats are often closely associated with female cats, male cats can also be calico. Uncovering the genetic mystery of sex linkage and the X chromosome is just one of the many subjects that continues to surprise and intrigue us.

If you're looking for a new feline friend, don't let the fact that male calicos are rare stop you from checking out a shelter or rescue for a unique bundle of fur; you never know what you might find!

Still bored? Check out our blog post on cat purr benefits.

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