Here is some important information I found on altering while researching for this site.

Definitions:
Spay - Medical term is ovariohysterectomy. A surgical removal
of the uterus and ovaries from the abdomen of a female animal.
Neutering - Also called castration is the surgical removal of
the testicles from the scrotum of a male animal.

- Spayed/neutered pets are healthier
- Males fight less and most will quit spraying to mark their territory
- Spaying female dogs and cats eliminates the possibility of uterine and ovarian cancer and greatly reduces the risk of breast
cancer.
- Neutering male dogs and cats reduces the risk of prostate cancer
- Spayed and neutered animals live longer and healthier lives
- In 6 years, one female dog can produce 67,000 puppies
- In 7 years, one female cat can produce 420,000 kittens
- Females first go into heat at around 5 months of age - sometimes earlier - and
can have litters up to twice a year
- Spayed/neutered pets get along better with each other since there is no challenge
for dominance.
- Spaying/neutering will make you animal less aggressive
- The typical time to have the surgery is at 6 months. However, I found that they
are now doing the surgeries much much sooner.

If you still think that spaying and neutering isn't necessary,
please read on. Or you can email me.