Puppy sex: how to tell a male from a female

If you came here after looking up the same thing for a cat, forget what you read there. In dogs the landmark is different. A kitten is sexed by comparing two openings under the tail; a puppy is sexed by looking at its belly. It is far simpler and far quicker.

🔎 The rule: look at the belly

Hold the puppy on its back, one hand under the loins. Follow the belly line from the navel backwards.

• Male — two or three centimetres behind the navel, a small furred bump with an opening: the prepuce. It sits well away from the anus, in the middle of the belly.

• Female — nothing on the belly. The vulva is at the other end, just below the anus. You recognise it by its small teardrop shape pointing down.

👉 An opening mid-belly: male. Nothing on the belly: female. In dogs the gap between anus and genital opening tells you nothing — unlike cats, where it is the only measure that counts. If you are looking for a kitten, read our guide to kitten sex instead.

🐾 The handling, in practice

A newborn puppy is sturdier than a kitten, but it still cannot regulate its temperature, and the dam dislikes having it taken away for long.

• Warm your hands and lift the puppy with both hands, never by the legs.

• Turn it on its back, along your forearm or on a towel.

• Look for five seconds and give it back. You see it straight away; there is nothing to hunt for.

• Do it during the daily weigh-in: the puppy is out of the nest anyway.

📅 What you can see at each age

• At birth — the male's prepuce is already there and visible. Sexing is reliable from the first check, the one you do anyway to weigh and count the litter.

• Two to eight weeks — the testicles descend. In dogs, unlike cats, this happens after birth. You feel them appear in the scrotum, two small beads below the anus.

• Six months — both testicles should be down. Beyond that, it is called cryptorchidism.

Cryptorchidism is not a breeder's quirk: it is disqualifying for breed registration and in the ring, and a testicle retained in the abdomen needs veterinary follow-up. Check at eight weeks, then again when buying the puppy.

🎨 In dogs, colour tells you nothing

In cats a tortoiseshell coat all but guarantees a female, because the orange gene sits on the X chromosome. There is no dog equivalent. No coat, no marking, no birth weight gives the slightest clue about sex.

The biggest puppy in the litter is no more likely to be male. Nor is the quietest. Only the anatomy answers.

⚠️ The four classic mistakes

• Looking under the tail. That is the cat method. On a puppy it shows only the anus, and a vulva if it is a female — but you miss the prepuce, which is elsewhere.

• Confusing navel and prepuce. The navel is a flat scar, sometimes still a little thick in the first days. The prepuce is behind it, and it has an opening.

• Concluding without parting the fur. On a long or wire-coated breed the prepuce hides. Part it gently.

• Forgetting to recount. In a litter of eight, a mix-up happens fast. Check again at three weeks and write it down.

📋 Why it pays to know at once

• The litter declaration. It is filed in the days after whelping and carries the sex of every puppy. A mistake then has to be corrected by hand with the stud book.

• Identification. The sex appears on the identification record, required before any transfer.

• Reservations. Families reserve on sex before they have even seen the puppies. A late correction undoes a whole waiting list.

• Neutering. The timing and the cost differ between male and female.

• The name. In France the year of birth sets the initial letter: see our guide to dog names by year.

🩺 When to ask the vet

A puppy's sex is beyond doubt after a few days. What the vet checks is the descent of both testicles, at the first vaccination and at the booster. That is also the identification appointment.

For the rest of the litter, two guides go with this one: the kit list for a bitch giving birth and whelping in dogs and cats.