Can you imagine discovering for the first time that your male dog is actually a female? This would certainly be a very confusing time for you! This can in fact be the case in some dog breeds and canine sex reversal is unusually common in cocker spaniels. This article intends to dive into the world of canine sex reversal and aims to provide a basic understanding of this topic.
What is canine sex reversal?
Let’s start at the very beginning. Sexual development begins in utero where there are a series of steps under genetic and hormonal control. Disorders of sexual development can occur during these steps which leads to atypical differentiation of the gonads (testes/ovaries) and genitals.
Genetics is a very complex topic which I won’t dive too far into, however, it is relevant to know that in the early development the sex chromosomes are established as XX (female) and XY (male). Only XX sex reversal has been discovered in dogs. Canine sex reversal describes a condition where the chromosomal and the gonadal sex differs, meaning that your dog could be both male and female genders.
There are many disorders of sexual development, however, this article will focus on the disorder of ‘phenotypical sexual development’ in cocker spaniels, also known as pseudohermaphroditism. Pseudohermaphroditism can occur in many species but today’s focus is in our canine friends, particularly cocker spaniels. Other relatively commonly affected breeds include Beagles, Miniature Pinschers and Norwegian Elkhounds (this list is not exhaustive).
Dog’s with this condition (XX male) will have testes, but will possess the XX chromosomes of the opposite sex (Kim et al, 2019). The other genitalia may be more female, more male, or somewhere in between. In contrast to this, a true hermaphrodite dog will have female chromosomes but will have both ovaries and testicles.
How is it diagnosed?
So of course you are going to wonder how we find out whether or not your dog has canine sex reversal. Suspicions from your Veterinarian can be made from the clinical examination. Dogs with canine sex reversal may have physical abnormalities such as vulval enlargement or an abnormal penis. Sometimes these abnormalities to their external genitalia can actually be irritating for your dog and as their Owner you may notice them paying a lot of attention to these areas.
Additionally, the next diagnostic step may include blood tests to identify the chromosomes – although the samples are usually sent away because these unique tests can only be performed at special laboratories. Your Vet will also check your dog for internal reproductive organs either via imaging (ultrasound scan) or surgical exploration.
What does it mean for my dog?
Be reassured that dogs with canine sex reversal can still live a normal and happy life. However, they are usually infertile and are unable to breed successfully. Furthermore, even if these dogs are able to reproduce it is absolutely not recommended to do so. Canine sex reversal is an undesirable condition and in order to be responsible we should aim to neuter affected animals to stop these traits being passed onto offspring. Neutering them is the treatment of choice and this involves surgical removal of the gonads (whatever they are) and uterus if present.
To conclude, canine sex reversal is a fascinating condition that is not seen too often in first opinion Veterinary practices. Thankfully dogs with this condition can still live a normal lifespan, but neutering these dogs is definitively recommended both for their best interest and to protect the health of future generations.