Neutering pet rabbits is highly advisable if they are not to be used for breeding. An obvious reason is that rabbits are very good at finding mates and can have many kittens in one litter. Breeding rabbits is a big commitment and rabbits should not be bred if their background is unknown as there could be a family history of dental disease, behavioural problems and a range of other inherited disease.
It is recommended that rabbits are neutered from as early as 12 weeks of age (boys) or 16 weeks (girls) as it is from this age that sexual maturity may occur.
Neutering also reduces the risk of unwanted behaviour; castrating a male will prevent inappropriate mounting and urine spraying, spaying a female can reduce aggression and both will tend to be calmer with other rabbits if neutered. Uterine cancer is also common in the pet rabbit in mid-late life, so spaying young will reduce the risks of this.