Veterinary Advice Online - Sexing Puppies and Dogs.

A newborn puppy. Some dog owners find it very difficult to determine the sex of puppies, particularly newborn pups, and often need their veterinarian to sex their puppies for them.

Now you can determine the sex of your pups all by yourself!

This page contains everything you, the pet owner, need to know about sexing puppies and dogs. Information provided on this page is supported by a number of helpful pictures and photographs that clearly illustrate how to distinguish the boys from the girls. Topics are covered in the following order:

1. Some basic dos and do nots when handling and sexing puppies for the first time.

2. How to tell male pups from female pups.

1. Some basic dos and do nots when handling and sexing puppies for the first time.

There is not too much that can go wrong when attempting to determine the sex of puppies, however, I will draw your attention to a couple of important puppy-handling dos and do nots, which should be taken into consideration.


  • Handle your puppies gently.
  • Rest your puppies on a clean towel on their backs or cupped in your hands on their backs to examine their genitals.
  • Where possible, wait to sex pups until they are over 3-4 weeks of age.
  • Make sure that your bitch (the mother dog) is comfortable with you handling her puppies before proceeding to touch them.
  • Put whelps (pups) back with their mother immediately if they become distressed from handling.
  • Handle young puppies in a warm area and for no more than 5-10 minutes at a time so that they do not get cold.

  • Handle puppies roughly.
  • Pick pups up by their tails or hang them by their tails (they are not mice!)
  • Handle newborn puppies (pups under 3 weeks of age) if you can avoid it. Mother dogs (especially new mothers) can become uncertain of their new puppies if you handle them too much and get your human smell all over them. This can potentially lead to the mother dog rejecting her pups.
  • Handle pups if they are still suckling (not yet weaned) and their mother is clearly distressed by you handling them. This can result in dog bites and rejected puppies.
  • Handle newborn puppies (<3 weeks old) for long periods of time. They can become cold away from the nest.
  • Attempt to expose or pull out the penis of prepubescent male dogs (dogs under 6 months of age). Such animals are not capable of exposing their penis and attempting to do so forcibly can damage the penis.


2. How to distinguish male puppies from female puppies.

The best way to determine the sex of male and female puppies is to rest the puppies on their backs on a warm (not hot) towel or cradled on their backs in your hands and examine their bellies and genitals. There are several differences that exist between male and female puppies, even newborn pups, which you can look out for when sexing puppies.

Important note - only keep pups on their backs for a short period of time: just long enough for you to determine their sex. Keeping them on their backs too long can be distressing to them.

1. Male puppies have a penis in the middle of their belly just behind their umbilical cord. Female puppies do not.

Look at the pictures below. These are close-up photographs of the bellies of two individual 2-day-old sibling puppies. The first puppy (pup on the left) is a young male and the puppy beside it (on the right) is a young female.

Male puppy sexing - male pups have a penis in the middle of their belly just behind their umbilicus.The belly of female puppies is bare and smooth behind their umbilicus. Their genitalia (vulva) is located between their legs.
What you will notice from these two images is that the male puppy (pup on the left) has a small raised lump in the middle of its belly approximately 0.5-1cm behind (caudal to) its umbilical cord. This small lump is the male puppy's penis. The belly of the female puppy (puppy on the right) is bare behind the umbilicus. The female's genital structures (vulva and vagina) are located far back between her legs (just beneath her anus), not on her belly like the male's genital structures are.

2. Female puppies have a leaf-shaped vulva. Males have a rounded penis.

Look at the picture below. This is a close-up photo of the genitals of a 2-day-old female puppy.

Sexing female puppies - The vulva structures of a female pup.
What you will notice from this image is that the genital opening (vulva) of the young female puppy is shaped like a pointed leaf and contains a vertical slit-like opening (the entrance to the vagina).

In contrast, the penis of the male puppy (image below) is rounded like a button and contains a central dot-like genital opening (the entrance to the urethra).

Determining the sex of male puppies - the penis of a young male puppy.


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Copyright November 13, 2008, Dr. O'Meara BVSc (Hon),
All rights reserved, protected under Australian copyright. No images or graphics on this Pet Informed website may be used without written permission of their owner, Dr. O'Meara.