Neutering can have a positive impact on your Dog's life

Males dogs are neutered, meaning the testicles are surgically removed. This is a commonly performed procedure. He usually can go home the same day, and return to regular activities within a few days. See: Wound Care
Females dogs are spayed, which surgically removes their ovaries and uterus. Surgery is more involved for females, since an incision is made in their abdomens. An eCollar can help. Female dogs also usually come home within 24 hours, have limited activity until the stitches start to heal (for two or three days), and then return to regular activities within a week to 10 days.
Puppies can be altered as young as four months.
Females should be spayed before their first heat.
Low cost spay/neuter clinics are available in every community. Contact your local animal shelter, or ask your veterinarian for names of clinics near you.

Prevent pet overpopulation: Over 7 million healthy dogs and cats are put to death every year in Animal Control facilities in the U.S. because there aren't enough homes for them.
Fewer behavior problems: Intact dogs dig out of yards, jump fences, and run away from home more often than altered dogs. Male dogs can smell a female in heat at a great distance away. Neutered males are also less likely to mark their territory.
Less aggressive: Altered male dogs are less aggressive towards other dogs than intact males. Altered females are also less aggressive, since a mother may become aggressive if she thinks her puppies are threatened.
Better health: Female dogs are at risk for mammary or uterine cancer. Male dogs often get testicular or prostate cancer. These risks are reduced or eliminated as soon as your dog is altered. They are also less likely to escape your yard and get injured while running loose.
Females do not go into heat: Female dogs in heat are messy, and can leave stains on your furniture and carpet. Heat "seasons" can last up to three weeks, twice a year. Four Paws Sanitary Pads The scent of a female in heat can attract males from a great distance away.

"My dog won't be able to hunt as well." Neutering has no effect on your dog's ability and instinct to hunt. Your dog will actually be less distracted by other dogs, and better able to concentrate on work.
"Altering makes them fat and lazy." Overeating makes dogs fat and lazy, not spaying or neutering. There are lots of overweight intact dogs out there. Your dog will be healthy and live longer when altered.
"I want my children to experience the miracle of birth, and puppies are so cute". Pregnancy is not risk-free. Are you willing to risk losing the mother dog? Are you willing to do the work to find responsible homes for every puppy she produces? There are thousands of dogs and puppies euthanized every year.
"My dog's old." Your dog is almost never too old for spay/neuter surgery. Unless your veterinarian finds a health reason to avoid surgery, go ahead and have it done. You could combine the procedure with another, like teeth cleaning.