America is drowning in dogs. Shelters try, but millions are euthanized every year because no one wants them. The single biggest problem causing this is irresponsible owners who don't have their pets neutered. Unless you breed Labradors, take your pet out of the baby business.
Neutering is a general term for making sure your Lab doesn't become a parent. The technical term can include both males and females, but is used more commonly in reference to males.
Neutering requires a surgical procedure to remove the testicles of a dog and the ovaries and uterus of a bitch. It is done under general anesthesia, which makes it painless. The male's testicles are removed through a small incision in the scrotum or sac, while the bitch's uterus and ovaries are removed through an incision in the midline or center of her belly. Your Labrador may be able to come home the same day as the surgery for lots of TLC and should have little to no discomfort if you follow your vet's instructions carefully.
It tends to make Labradors more popular with both humans and other dogs. They're usually friendly and well behaved, but you don't want 50 or so pounds of dog clinging to your leg and humping away every few minutes or the same size bitch running through the house in a frenzy of sexual frustration, dripping bloody fluid everywhere. Your big boy will make more friends at the dog park or doggie day care if he's not pestering an unreceptive bitch or starting a fight with another male. If you're a hunter, your sweet girl will be able to concentrate better on fetching birds if she's not humming "Hot Stuff" under her breath. Neither one can possibly get cancer or any other disease in an organ that isn't there any more. Neither one will have a radical personality change or get fat just because of neutering.
The best time to neuter any dog is after he's full grown but before he hits puberty. Labs tend to be late developers and can sometimes not reach their full growth until 2 years of age, but sexual maturity can come before that. Bitches seem to do best if spayed before their first heat cycle and certainly before they've had a litter. Six months of age is about the right time to consult your vet about taking care of this important aspect of your Lab's health and well-being. Together you can judge where your pet is developmentally and whether it's time to relieve your pal of that biological imperative, the need to breed.