The castration of dogs is an emotive issue which veterinary surgeons and behaviourists sometimes recommend to help cure certain behaviour problems. Sometimes the idea is met with resistance, particularly by some male owners, despite all the evidence and arguments raised in favour of the operation. The subject of castration has to be dealt with rationally as there are definite circumstances where the surgical removal of a dog's testicles can help to improve problem behaviour. Indeed, castration can help prevent the development of some behavioural problems which in addition to the prevention of unwanted litters, is a good reason for the neutering policy adopted by many rescue organisations. Sadly there are occasions when this occurs, normally because the operation was not appropriate in the circumstances.
Accurate diagnosis is therefore essential to determine whether castration is appropriate.
As a rule of thumb, castration is most likely to be curative when the problem behaviour is sexually dimorphic. In other words, it is specific to, or more common in, one sex than the other. Males exhibit behaviours which are influenced by testosterone, such as scent marking, roaming away from home to find potential mates, inappropriate sexual behaviour, aggression towards other males, and sometimes rank related aggression within the family which is its substitute pack. Even when castration is relevant, there is only a percentage chance that it will work. This is because the male brain is programmed to display male behaviour by testosterone even before birth.