A puppy’s testicles typically descend into the scrotum by two months of age. They develop near the kidneys while the puppy is still in the womb, then gradually migrate downward through the abdomen and into the scrotum during the first weeks of life. If one or both testicles haven’t arrived by six months, the puppy is considered cryptorchid, meaning the testicle is retained somewhere it shouldn’t be.
The Normal Timeline
Testicles form deep in the abdomen, close to the kidneys, while a puppy is developing in utero. A band of tissue connects each testicle to the developing scrotum and acts as a guide rope, helping pull or direct the testicle downward through a narrow passage in the abdominal wall called the inguinal canal. In most puppies, both testicles complete this journey and settle into the scrotum by about eight weeks old.
Some puppies run a little behind schedule. A vet may flag a concern if testicles aren’t palpable at the eight-week checkup, but the official cutoff for diagnosis is six months. After that point, the inguinal canal has typically closed enough that further descent is unlikely. So if your puppy is three or four months old and you can only feel one testicle, there’s still a reasonable window for the second to show up, but it’s worth mentioning at your next vet visit.
How to Check at Home
You can gently feel your puppy’s scrotum to check whether both testicles are present. You should feel two small, round, firm structures that move freely within the sac. In very young puppies, the testicles are tiny and can retract upward temporarily when the puppy is cold, stressed, or squirming, so a single check isn’t always definitive. Try again when your puppy is calm and warm. If you consistently can’t feel both testicles after about four months, have your vet take a look.
What Happens When a Testicle Doesn’t Drop
When one or both testicles fail to descend, the condition is called cryptorchidism. The retained testicle can end up stuck in one of a few places: inside the abdomen, within the inguinal canal (the passageway through the abdominal wall), or just under the skin in the groin area between the canal and the scrotum. If the testicle is sitting in the inguinal canal or under the skin, your vet can usually feel it during an exam. Abdominal retention is harder to detect from the outside and typically requires ultrasound to locate.
Cryptorchidism can affect one testicle or both, though one-sided cases are more common. It’s one of the most frequently seen developmental conditions in male dogs.
Breeds With Higher Risk
Any dog can be cryptorchid, but certain breeds are overrepresented. German shepherds, boxers, and chihuahuas show higher rates than average. The condition runs in families, which points to a strong genetic component. Because of this heritability, cryptorchid dogs and their close relatives are generally not recommended for breeding, even if the retained testicle is surgically removed. Breeding a cryptorchid dog increases the chance of passing the trait to the next generation.
Why Retained Testicles Are a Health Concern
A testicle that stays inside the body is exposed to higher temperatures than it was designed for. The scrotum exists specifically to keep testicles a few degrees cooler than core body temperature, which is necessary for normal sperm production and tissue health. When a testicle remains in the abdomen or inguinal canal, that temperature difference disappears, and the risk of serious problems goes up substantially.
The biggest concern is cancer. Studies have found that cryptorchid dogs face a 9 to 14 times higher risk of developing testicular cancer compared to dogs whose testicles descended normally. For certain tumor types, the risk is even more dramatic: retained testicles show up to a 23-fold increase in one type of tumor and a 16-fold increase in another. These aren’t rare odds. The longer a retained testicle stays in the body, the greater the cumulative risk.
Beyond cancer, retained testicles can also twist on themselves, cutting off their own blood supply. This is a painful emergency that requires immediate surgery.
Treatment for Cryptorchidism
The standard treatment is surgical removal of the undescended testicle. Most vets recommend neutering cryptorchid dogs entirely, removing both the retained testicle and the normally descended one. This eliminates the cancer risk from the retained side and prevents the dog from passing the genetic predisposition to offspring.
If the testicle is in the inguinal canal or just under the skin, the surgery is relatively straightforward. Abdominal retention requires a more involved procedure, sometimes with laparoscopic assistance to locate and remove the testicle. Recovery is generally quick, similar to a standard neuter, though abdominal cases may need a few extra days of rest.
There’s no reliable way to coax a retained testicle into descending on its own after six months. Hormonal treatments have been tried but aren’t considered effective or recommended, partly because even if they worked, breeding a cryptorchid dog would still spread the genetic trait.
What to Expect at Each Stage
- Birth to 8 weeks: Testicles are migrating. They may be small and hard to feel, especially in tiny breeds. Your breeder or vet should check before you bring the puppy home.
- 8 weeks to 4 months: Both testicles should be palpable in most puppies. If one is missing, it’s worth monitoring but not yet a definitive diagnosis.
- 4 to 6 months: The window for natural descent is closing. If a testicle still isn’t in the scrotum, plan to discuss it with your vet.
- 6 months and beyond: The diagnosis of cryptorchidism is confirmed. Your vet will recommend imaging if needed and discuss surgical timing.