Neutering can make for a better and more affectionate family pet. It is a medically proven that spaying and castration can prolong the life of dogs and may reduce the number of health problems in later life.  Females can benefit from spaying by reducing the incidence of uterine, mammary, and ovarian cancers. It can also reduce the incidence of uterine infections such as Pyometra. Castrating a male reduces the risk of prostate and testicular cancer. They are less likely to develop unwanted behaviour's such as marking, sexual aggression, and mounting, they are also less likely to escape, roam, or fight with other dogs. I am very much in favour of neutering, however it should be done at the right time.

Over the last 25 years I have noticed that the age of dogs being neutered has become increasingly young. During this time it has been a great concern to me and many other trainers and behaviourist agree that this is having a detrimental affect on many dogs.

I have noticed that the incidence of frustration, lack of attention, and puppy like behaviour, appeared to be far more prevalent in dogs that were castrated and spayed at a younger age, rather than those that were allowed to mature naturally before attempting this operation. For this reason I would recommend neutering after nine months and for bitches three months after there first season. As behavioural consultants and obedience trainers, I find that we are treating many more cases where dogs are displaying (paedomorphic) tendencies. That is puppy like behaviour's in adult dogs, which I believe is related to the incidence of early spaying and neutering. I have also noticed that bitches spayed too early, seem to be  far more interesting to intact males, this can sometimes cause the female to become aggressive and protective of this attention in adulthood.

I have also noticed that young bitches that show aggressive tendencies towards owners, especially before the age of six months; often demonstrate increased aggression after spaying. Spaying removes the production of progesterone, which is a natural calming hormone and a Serotonin up lifter. Spaying may therefore escalate any observable aggressive behaviour, either to humans or other dogs. Despite popular belief spaying does not calm a female dog down. It may help to calm certain behaviour's in males, but not female dogs.

Most male dogs will have a testosterone surge at between 9 and 20 months depending on breed .  Male dogs also produce Progesterone. Progesterone and testosterone switches on many of the hard-wired behaviour's we see in maturity. These may have social implications and behavioural effects that aid in the development of dogs psychological and physical growth. If we switch these off by neutering or castrating too early, we may be denying the opportunity achieve both mentally and physically the dog’s full adult potential.  Progesterone receptors are found in brain cells, in nerve sheaths and in bone cells, In both male and female dogs. indicating that progesterone is involved in their function. It also appears to be involved in a range of other biological activities. Therefore neutering before both physical and psychological maturity may have numerous other long-term detrimental effects.

I have noticed that if dogs have been neutered early they appear to retain a juvenile characteristic than those neutered when mature. Its as if, they retain perpetual puppy like characteristic, this can result in a dog that shows low concentration levels and frustrated puppy like behaviour for the remainder of its adult life.