You need to know the sex of your puppies so you can decide how to deal with them when they become sexually mature. Determining the sex of newborn dogs is easier than with newborn cats, because the genitalia are much more distinct in newborn canines. To tell the sex, say the people at PetInformed, gently hold the puppy on its back in your cupped hand and examine its belly side for the distinguishing signs of gender. This should take only a couple of minutes. Don't pick up a newborn pup by its tail. Immediately return the puppy to its mother if the puppy or mother shows signs of distress.
Signs of a Male
A newborn male puppy has a little lump like a rounded button on its belly, about a half-inch to the rear of its umbilical cord stump. This is the puppy's penis. Males also have a tiny round scrotum just below the anus and almost between the hind legs.
A newborn female puppy's belly is bare between the umbilical cord stump and hind legs. Females have a vulva resembling a pointed leaf with a slit in the middle, located just below the anus and almost between the hind legs. Don't be fooled by the nipples. Both male and female dogs have nipples.
As your pup grows to sexual maturity, you'll be faced with the question of whether to have it desexed. Unless your puppy is a purebred, show-quality pooch, the dog care experts at Puppy Dog Place recommend you have it desexed at around 6 months of age. They say desexing all but eliminates the risk of reproductive-system diseases, increases life expectancy by an average two years, curtails undesirable sex-linked behaviour and ensures that you'll never have to deal with an unwanted litter of puppies.
Veterinarians neuter male dogs by surgically removing the testicles from the scrotum, which is a relatively simple external operation that doesn't require opening the dog's body cavity. The operation is done after the dog's testicles descend into the scrotum, usually at around 4 to 6 months of age. Neutering males as early as possible helps reduce marking and spraying behaviour and helps curb a male's drive to wander the neighbourhood in search of a female in heat.
Veterinarians spay female dogs by opening the abdomen and surgically removing the ovaries and uterus. This is a more complex operation than neutering a male, with a longer recovery time. Ideally, spaying should be done before the dog goes into her first heat, which typically occurs at around 6 months of age. But it can be done later. If she's not spayed, you'll have to put up with male dogs at your doorstep every three weeks or so, desperate to get at your female in heat. And if any of the males succeed, you'll be dealing with an unwanted canine pregnancy.