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Is It Safe To Breed Brother and Sister Dogs?

↯ Key takeaway points

  • Inbreeding in dogs has potential health risks and reduces the breed's gene pool, leading to potential long-term health problems.
  • Inbreeding siblings can produce predictable traits related to temperament and appearance, but genetic screening is crucial before attempting to breed them.
  • Inbreeding siblings also risks weaker immune systems, more prevalence of autoimmune disease, more aggression in offspring, and reduced intelligence.
  • Coefficient of Inbreeding (COI) needs to be considered, and it is generally recommended to keep it no higher than 5%.
  • Breeding siblings should only be attempted after seeking advice from professionals, considering the risks and ethical implications.
Breeding Business is passionate about all sorts of domesticated pets. They have written dozens of articles across the web.
Gold medalist veterinary student from UVAS Lahore writes captivating articles and is passionate about animal care.
Published on
Wednesday 6 June 2018
Last updated on
Thursday 18 May 2023
breeding brother and sister dogs
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On most occasions, it is generally considered dangerous to breed brother and sister dogs together. This is because of the risk of long-term health complications. Even if inbreeding is carefully planned and managed, it still has the potential to cause other indirect problems over time.

However, a certain degree of inbreeding is still required if dog breeds themselves are to continue to exist — otherwise Labradors will no longer look like Labradors, and so on. Nevertheless, it is recommended that dogs to be bred do not share the same the same parents or ancestors in a four-generation pedigree. This ensures the genetic material shared between a litter. Additionally, it ensures that parents are similar but not too similar that it will significantly reduce the gene pool over time.

Benefits of Mating a Brother to its Sister Dog

Most people associate inbreeding with incest in humans which is both illegal and medically wrong. However, completely different standards apply in the canine species. Inbreeding in canines is often seen as beneficial and is still perfectly legal. Dogs lack emotional maturity. So, a male dog will still naturally attempt to mate with his sister, without giving any thought to morals or repercussions. The copulatory tie will not require any additional assistance than it would usually. In fact, it might even be easier because the dogs are already known to one another. They should already be comfortable around each other and familiar with one another’s smell.

Brother and sister dogs are most commonly bred together to help produce puppies with predictable traits related to temperament and appearance. The general idea is that — in theory — if you have two dogs with exceptional health and aesthetics and you breed them together, they will produce one or more equally superb specimens.

[pullquote-right]Breeding dog siblings is rarely, if ever, recommended.[/pullquote-right]

A brother and sister dog will share far more genetic material than two unrelated or distantly-related canines because they share the same parents. Therefore, breeding a brother and sister dog together can fix or homogenise certain superior traits in dogs by increasing the likelihood that they will be passed onto the next generation. Some believe that this is the most efficient way to strengthen a breed of dog. This is because dogs within this bloodline will share more and more of the same superior genetic material.

This is how an official dog breed comes about in the first place — dogs with very similar traits repeatedly breed until a group of dogs have a certain look about them, then a breed standard is officialized, and the actual dog breed exists. Therefore, Labradors look like Labradors and Pomeranians look like Pomeranians.

This process of breeding a brother and sister dog together can be considered a lot simpler logistically. A dam owner can spend months seeking out a stud that complements their dam. They will then have to pay fees and sign a stud service contract to have access to the stud for breeding. If the dam can instead be mated with one of her brothers, the time taken to locate and secure a stud is significantly reduced.

Additionally, canine incest (if done by an experienced breeder) can sometimes provide some peace of mind. You will have more of an idea about what to expect from a litter. However, siblings or not, both dogs should still undergo genetic screening, so you can learn about all their genetic material, both good and bad. It is important not to become complacent or irresponsible or you may end up exacerbating any negative traits in future pup(s).

Risks of Breeding Siblings in Dogs

Unfortunately, it is not correct to assume that two dogs who share strong genetics will always produce the perfect litter; free from disease, disability or illness. Two dogs who do not outwardly display certain negative traits or characteristics, may still be a genetic carrier and carry recessive alleles which, when combined at a later breeding, cause negative traits to manifest in their offspring. Consequently, it is not uncommon for inbred dogs to experience problems such as hip dysplasia and heart and liver conditions at some time in their lives. Therefore, you must always carry out a full genetic risk assessment before attempting to breed a brother and sister dog together — even if (on the surface) they seem perfect.

Reducing the Size of the Gene Pool

Breeding sibling dogs together also reduces the size of a breed’s gene pool which is widely viewed as a bad thing from an evolutionary standpoint. Certain breeds become prone to certain diseases (and to death from certain diseases) because their gene pool is so limited that it is difficult for future generations to avoid inheriting genes that predispose them to these diseases.

For example, Great Danes are prone to potentially fatal conditions such as bloat, meaning they have a life expectancy of just 8-10 years, whilst the Dogue de Bordeaux is prone to breathing difficulties and overheating and is therefore expected to live no more than 5-8 years. If the Great Dane and Dogue de Bordeaux are perpetually bred with their siblings, their genetic line will forever experience health problems of this calibre because there are not enough dogs with predominantly good genetic material in the gene pool to improve and reinforce the health of the breed.

Inbreeding Depression


Furthermore, if a breed becomes too inbred, it may be subject to inbreeding depression whereby its ability to thrive and continue its genetic line decreases. Too many harmful recessive alleles become present in the population’s gene pool. Thus, in the same way that it becomes more likely that when you breed a brother and sister together they will share the same good genetic material, it also increases their chances of sharing the same bad genetic material. The frequency of this bad genetic material will increase within the population’s gene pool as breeding continues through future generations.

For this reason, animals in the wild have their own highly organised social setups to avoid inbreeding altogether. For example, hyenas will only breed with female hyenas in a pack separate from their own. It is by mechanisms such as these that they avoid inbreeding depression, which could lead to extinction of the species all together — or at the very least, a significantly reduced life expectancy (which has already happened with the Great Dane and Dogue de Bordeaux, for example).

Weaker Immune System

Many breeders who have bred siblings have also found that the puppies have weaker immune systems. They also noted more prevalence of autoimmune disease. They can become seriously ill from common infections and colds than other dogs with greater genetic diversity. Some breeders have also noticed that inbred offspring are more aggressive and less intelligent, making them more difficult to train and control.

Research suggests that the only way out of this trap is to outcross which means breeding dogs together that are not closely related to widen (and improve) the breed’s gene pool. The genes can still be of the same breed but should not share the same parents or share common ancestors within a four-generation pedigree. What makes a species strong and long-lasting is its genetic mix and variety; reducing it leads to no good if done consistently over several generations.

Should I Breed Brother and Sister Dogs?

If you are considering breeding a brother and sister dog together, it is not a decision that should be made lightly. Both dogs must undergo full genetic screening and you should seek advice from a vet about possible implications of breeding these siblings together. There will be rare times when it is smart or required to inbreed and oftentimes when it isn’t. If you are asking yourself the question, then it is probably NOT a good idea to go ahead with such close linebreeding.


The only real benefit to inbreeding siblings is to keep hold of one or more favourable traits and move those down the genetic line. If you are thinking about breeding two siblings together, you should evaluate how important these traits are to the breed and whether these outweigh the potential problems that may also be brought on as a result.

Coefficient of Inbreeding

It is useful to consider the Coefficient of Inbreeding (COI) which is the likelihood that two copies of the same gene from a stud and a dam will be inherited by a potential pup. The higher the COI, the higher the risk of inbreeding and the more health complications the dog is likely to have. It is generally recommended within the breeding business that a COI be no higher than 5%. Typically, breeding a brother dog to its sister dog will result in a COI of around 25%, which puts the pup at a dangerous level of risk. Therefore, both the dam and stud should have an exceptionally clean genetic profile before any attempts at mating begin or there is a high chance the pup will inherit any negative genetic material present.

There are also ethical decisions to be made here. As the owner of a brother and sister dog that you are interested in breeding, you should consider how you the owner will feel if your dam gives birth to puppies with congenital birth defects consequential to inbreeding. This can be quite distressing for you, the mother dog and the pup. The mother may reject one or more of her pup(s) if they are sickly or weak and there is a chance they may not survive. You should consider whether the stress placed on all involved is truly worth it. If you still decide to go ahead, never do anything without advice from professionals, as there are lives at stake!

Alternative Solutions to Genetic Health Problems in Dogs

Some alternative solutions to genetic health problems in dog breeds could include outcrossing, which involves breeding dogs from different but related breeds, and backcrossing, which involves breeding a dog from a different but related breed back to a purebred dog of the original breed to reintroduce desirable traits while maintaining genetic diversity. Another solution could be using genetic testing to identify and avoid breeding dogs with certain genetic health problems. Additionally, some breeders may also choose to focus on selecting for overall health and longevity rather than specific physical traits that may be associated with health problems.

16 comments on “Is It Safe To Breed Brother and Sister Dogs?”

  1. Tina Novak

    Very excellent, professional and educational articles. It’s always a pleasure to read. Thank you. Tina/pooch parlor

    1. Angie

      Were we watching the same “Is It Safe To Breed Brother and Sister Dogs?”

      1. Spfia


      2. Aaron

        How about their children can we stud the sisters children?

  2. Angie

    My god, redneck Americans…lets all start breeding with our siblings ;)

    1. LynneLindley

      Is it safe to breed a grandson to grandma. I have a male who has a different father than the mother. But grandma is mother to his mother. Is that to close to bred grandmother to grandson ?

    2. Lana Banana

      It is NOT the same as humans inbreeding. Do your research before you spit ridiculous comments.

  3. Mary Beth Stultz


  4. Tama Underburger

    I am taking care of my son’s Chiweeni and I have the sister. I think the male might have mated with our female. They are only 9 months old. Would it be a major problem? What do I do. I don’t breed dogs at all.

    1. Colleen Lightkep

      Did you get an answer to this? My friend is ready to deliver these pups.

    2. Linda

      So what happened ? Did they mate ? Did you have a litter of puppies ? Were the puppies all ok ?

  5. Connie Bryant

    I have 2 chihuahuas, marly is my first baby, Max was given to me as a gift. I had Marly way before Max. They have the same mom but different dads. Max got Marly before I could do anything. I hate what happened but am In the red works to get her fixed. Was I in the wrong to let my baby have these pups? Am worried now…

    1. Lana W

      No it’s not wrong, it’s not like humans inbred. How did the puppies turn out?

  6. Hunter

    I have a male dog and one of my friend have a female both same dad but deferent mum we are checking is it’s safe to breed them together or not can any breeders help plz

  7. dan

    brother and sister are from two different litters and possess amazing traits genes show no sign of long term health issues.

  8. CC

    Millions of dogs are euthanized in the U.S. every year. Please visit your local animal shelter, foster, volunteer, adopt!

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