Good reasons to spay your female

Health reasons top the list.
Spaying offers complete protection against serious uterine infections such as pyometra and endometritis. These infections are common and they can be killers, especially of small females. Spaying offers complete protection against the hormonal upsets of false pregnancy. Spaying offers partial protection against breast cancer.
Risks of pregnancy.
Giving birth is risky and could cost your female's life. Dealing with puppies means a major change in your life.
Bloody discharge.
Twice a year, unspayed females come into "season" or "heat" and have a bloody discharge that can stain your carpets and furniture.
Swollen genitals, licking, and "flirting."
During her heat period, the genitals swell. Many females spend a lot of time licking their private parts. Many females flirt shamelessly with other dogs (even with other females), presenting their rumps and encouraging the other dog to mount them.
Humpiness!
Many females in heat will mount other dogs and hump pillows or stuffed toys.
Mood changes.
Some females become more restless, more moody, or more flighty during their heat period.
Heat periods can interrupt your daily schedule.
During the heat period, you often need to curtail daily walks or change your route so you're not passing the yards of male dogs. And friends and relatives may not appreciate your dog visiting at this time.
License fees.
In many communities, dog license fees are highest for unspayed females.


Possible disadvantages of spaying your female

Risk of surgery.
Spaying is major surgery requiring general anesthesia. This always carries some risk, especially with a breed who is notoriously difficult to anesthetize, such as toy breeds, flat-faced breeds (Bulldogs, Pugs), sighthounds, and giant breeds.
The expense.
Spaying costs one to two hundred dollars when the safest anesthesia is used and all safety precautions taken. Low-cost spay clinics are available, but I do not recommend these, and definitely not for the breeds listed above.
Can't show in conformation classes.
You can't show a spayed dog in conformation classes at dog shows, but I don't think much of these anyway -- and you CAN still show her in every other canine activity, such as obedience, agility, tracking, and so on.


When to spay

If you spay before the first heat...
Your female's risk of developing a breast tumor later in life drops from 1-in-4 to 1-in-200. That's excellent. BUT... breast tumors are usually benign. And the disadvantages of such early spaying are...
Increased anesthesia risk -- because of smaller size (especially in breeds that are small to begin with) and because of immature lungs/organs that have to withstand the stress of the anesthesia.
Tendency to mature with a somewhat "rounded", somewhat "generic" body shape -- because the reproductive hormones didn't have enough time to stamp in distinctive feminine characteristics.
Tendency to develop incontinence (leaking urine) in middle age. I'll let Dr. Friday explain this one...

Good reasons to neuter your male

Behavioral reasons top the list.
Unneutered males are more likely to "mark" their territory, which means spraying urine on every vertical object so other males can smell it. Marking can be an obsession with some males, especially in toy breeds and dominant breeds. They will tow you toward every fire hydrant and telephone pole. Some will mark inside your house, too.
Unneutered males are more likely to pick fights with other males. They are also more likely to be attacked by other unneutered males, who see them as potential rivals.
Unneutered males often get aroused easily -- the signs of which can be embarrassing. They lick themselves and hump other dogs, pillows, stuffed animals, and sometimes people's ankles.
Unneutered males are easily distracted. Their eyeballs tend to rove up the street looking for females or potential male rivals, rather than focusing on YOU.
Unneutered males can be hard to control when a female is in heat. They become agitated, whining and drooling and pacing and attempting to escape their house or yard.
Unneutered males are more dominant. Their testosterone goads them into resisting and challenging authority -- which means YOU.


Health reasons.
Neutering offers complete protection against testicular cancer. Neutering MAY offer partial protection against prostate disease.
If your dog has retained one or both testicles up inside his body, it is essential that he be neutered. A retained testicle is hereditary, so you mustn't breed him or he will pass on the condition. And a retained testicle is very likely to develop cancer unless removed.



License fees.
In many communities, dog license fees are higher for unneutered dogs.


Possible disadvantages of neutering your male

Changed temperament.
Some males do become overly placid after neutering -- but in my experience, these are in the minority.
Risk of surgery.
Neutering does require general anesthesia, which always carries some risk, especially with a breed who is notoriously difficult to anesthetize, such as toy breeds, flat-faced breeds (Bulldogs, Pugs), sighthounds, and giant breeds. However, neutering a male is simpler than spaying a female, and the male is not under anesthesia for very long. The exception is when one or both testicles have been retained. This surgery is more complicated.
Can't show in conformation classes.
You can't show a neutered dog in conformation classes at dog shows, but I don't think much of these anyway -- and you CAN still show him in every other canine activity, such as obedience, agility, tracking, and so on.


When to neuter

Toy breed males mature quickly and should be neutered at five to six months to prevent the obsessive leg-lifting and territorial marking habits they are prone to develop.
Larger breeds take longer to develop, so I prefer to wait until nine to twelve months before neutering. Males who have been neutered earlier tend to mature with a somewhat "rounded", somewhat "generic" body shape -- because the reproductive hormones didn't have enough time to stamp in distinctive masculine characteristics.