Since they will soon be facing the snip I thought it best to give you the low-down on neutering your cats
From around the age of 5 to 8 months, kittens reach sexual maturity and are therefore capable of breeding and producing kittens themselves! Most people do not have the time or desire to breed from their cat and do not wish to add to the number of unwanted cats and kittens already looking for homes. Neutering a cat - castration in the male (removal of the testes), and spaying the female (removal of the ovaries and uterus) - not only prevents unwanted pregnancies occurring, but also curbs unwanted behavioural patterns associated with sexual maturity and reduces the risk of certain diseases.
Spaying a female
In the past it has been suggested that all female cats should be allowed to have one litter of kittens. However, this is totally unnecessary and of no benefit whatsoever to the cat. It is therefore preferable to have a female spayed before she reaches sexual maturity. Once sexual maturity is reached, the cat will begin to come into season or 'call'. Cycles of sexual activity typically occur every three weeks, and when a cat is 'calling', as its name implies, this can be a very noisy affair! Certain drugs can be used to suppress the sexual cycle, but these carry quite a risk of significant side effects in cats and are not recommended for long-term use. If you are not going to breed from your female kitten, having her spayed will eliminate the sexual behaviour, the possibility of unplanned pregnancies and the risk of diseases associated with the genital tract later in life.
Castrating a male
Castrating a male is equally important as spaying a female to prevent unwanted pregnancies. Furthermore, entire male cats have a strong tendency to roam, to be aggressive to other males, to fight and to mark their territory by spraying urine (often indoors!). The aggressive behaviour puts an uncastrated male at much higher risk of serious infectious disease such as feline immunodeficiency virus (feline 'AIDS') and feline leukaemia virus, both of which are transmitted through cat bites.