Is It True That Cats Can Be Intersex? The Science Behind Feline Sexual Development Disorders

Cats can be intersex - the science has proved it. The term “intersex” is actually an umbrella term for sexual development disorders. In veterinary science, we actually use the term DSDs (Disorders of Sexual Development).

A hermaphrodite cat is exceptionally rare, but there are various documented cases in both peer-reviewed studies and stories of adoption from animal shelters. Essentially, an intersex cat is one that possesses both male and female sexual organs, and this presents in many ways.

In this guide, we will look at genetic and hormonal causes, take a look at methods of diagnosis of this phenomenon, and talk about what it means for a cat’s health outlook.

What Does “Intersex” Mean in Cats?

Intersex cats are born with a certain reproductive anatomy that doesn’t fit into the standard classifications for male or female. There are three criteria involved in classification of this anomaly in veterinary work:

• Chromosomal sex (XX, XY, XXY, mosaic)

• Gonadal sex (ovaries, testes or ovotestes)

• External genital appearance

Tests on these areas are important to determine a diagnosis of an intersex cat.

You may have heard the term "hermaphrodite" to describe this condition. This is actually an outdated term that is no longer used officially. Nevertheless, you may still hear it being used in media or as a colloquial word.

Types of Intersex Conditions in Cats

We have introduced the concept of intersex kittens, but there are actually different types of diagnosis that can come from this. Let’s look at the actual types of intersex conditions that have been documented in cats:

• Ovotesticular DSD: This might also be described as a “true hermaphrodite”. This is extremely rare, but cats that have this condition might have one ovary and one testis. Alternatively, they may have a combined ovotestis.

• Pseudohermaphroditism: In this diagnosis, the animal will have the gonads of one sex. However, the external genitalia may resemble the opposite sex. This means a male pseudohermaphrodite has testes but a female-like external anatomy, while a female hermaphrodite has ovaries but masculinised external genitalia.

• Chromosomal variations: This comes in 3 forms. They may have XXY chromosomes, similar to Klinefelter syndrome in humans, or an XX/XY mosaicism. Alternatively, they might have Chimerism (the fusion of two embryos).

It is important to know that most intersex cats are infertile. The condition often goes unnoticed, but is more likely to be discovered during spay or neuter surgery.

How Common Are Intersex Cats?

Intersex conditions in cats are actually very rare. Most of the available data comes from case reports, veterinary teaching hospitals and genetic studies. It is so rare that there is no exact population percentage available, but it is almost definitely less than 1%.

With that being said, there are some things to note. First, tortoiseshell or calico cats are strong indicators of chromosomal abnormality. This is because the tortoiseshell coloration is linked to the X chromosome. Colour genes for orange/black are X-linked in the following ways:

• Females (XX): They can show both colours.

• Males (XY): Usually, they can’t show both colours, unless they have a chromosomal anomaly.

Typical male cats cannot genetically be tortoiseshell without having one of the chromosomal variations that qualifies as an intersex cat (XXY chromosomes, mosaicism, Chimerism).

What Causes Intersex Traits in Cats?

Generally speaking, the causes of intersex traits in cats are genetic. The abnormalities can be related to the number of sex chromosomes, other abnormalities, mosaicism or chimerism. Let’s break these down a little to help you understand:

• Abnormal number of sex chromosomes: Essentially, this refers to males with XXY chromosomes, where most cats will only be XX or XY. There may also be XX/XY mosaics - we’ll go into this soon.

• SRY gene abnormalities: SRY stands for the sex-determining region on the Y chromosome. If there is some kind of malfunction here, it can disrupt normal male development.

• Mosaicism: This refers to a case where there is one embryo but two cell lines. Mutation occurs during early embryonic cell division.

• Chimerism: This is when two embryos combine into one. The two fertilised embryos fuse early in development, leading to chromosomal and genetic anomalies.

Intersex traits can also occur as a result of hormonal influences in utero. During foetal development, a cat might have abnormal exposure to sex hormones. This can result in masculinised female anatomy or ambiguous genitalia.

Hormonal imbalance is most likely to produce a pseudohermaphrodite. Even when chromosomes are typical, it can affect the external genital formation and lead to confusion once the kitten is born.

Are Intersex Cats Healthy?

In the majority of cases, intersex cats will live normal, healthy lives. This is why the condition often goes unnoticed - many known cases were discovered entirely by chance during a routine spay or neuter procedure.

There are some common signs that could suggest your cat is intersex. These include:

• An enlarged clitoris that resembles a penis.

• Undescended testes.

• Abnormal heat cycles.

• Infertility.

Though it is an unusual thing to do, a vet might be able to diagnose intersex traits in a cat. To do so, they would need to start with a physical examination. If there is cause for suspicion, this could be followed by ultrasound scans, hormone testing, and even chromosomal analysis.

If it is determined that an intersex cat’s health is at risk in any way, treatment could involve surgical removal of abnormal reproductive tissue. It would also likely involve spaying or neutering to ensure there is little risk of hormonal issues or reproductive cancers.

With all that being said, there is usually no need to worry about intersex cats. In most cases, they are:

• Not in pain due to their condition.

• Suitable for adoption.

• Normal cats with no behaviour issues.

Final Thoughts

Cats can be intersex. It is rare, but it is scientifically documented. Intersex traits in cats are usually genetic or chromosomal in origin, but most intersex lead healthy lives after veterinary care.

Intersex status does not reduce the quality of life of your cat. These cats can make loving companions, just like any other. However, if you notice unusual anatomy in your cat, we recommend that you get it looked at by a vet.