When Do Dogs' Testicles Drop? What to Do If Not
By Dr. Zubair Khalid, DVM, MS, PhD ·
Most dogs' testicles drop into the scrotum by the time they are 6 to 8 weeks old [1][2]. If you have a male puppy and you cannot feel both testicles by around 8 weeks, that is worth a veterinary check. The question of when do dogs testicles drop matters because a testicle that stays inside the body carries real health risks later in life.
This article is educational and is not a substitute for veterinary diagnosis or treatment.
Quick Answer
- Testicular descent is usually complete by 6 to 8 weeks of age, though some veterinarians allow up to 16 weeks before calling it abnormal [1][2].
- A testicle that never reaches the scrotum is called retained, and the condition is called cryptorchidism [1].
- Retained testicles can sit in the belly or in the groin, and right-sided inguinal retention is the most common pattern [1].
- Cryptorchidism is inherited, so affected dogs should not be bred [1].
- The standard treatment is neutering, which removes both testicles and lowers the cancer and torsion risks tied to the retained one [1][3].
What Cryptorchidism Means in Plain Words
A male puppy's testicles start out inside the abdomen. As the puppy grows, a cord-like band of tissue called the gubernaculum shortens and pulls each testicle down through a channel called the inguinal canal into the scrotum [1]. In most puppies, both testicles finish this trip by 6 to 8 weeks of age [1][2].
When one or both testicles fail to make that trip, the dog has cryptorchidism [1]. The retained testicle may stay in the abdomen or stop partway in the groin area [1]. A dog with one descended testicle and one retained testicle is sometimes called monorchid by owners, though the medical term is unilateral cryptorchidism.
Cryptorchidism is one of the most common developmental disorders of the male canine reproductive system [2]. It affects somewhere between 1% and 10% of the dog population [2]. Some reviews put the upper estimate at about 10% [4].
Signs Owners Notice
The main sign is simple. You cannot feel two testicles in the scrotum.
In a young puppy, the scrotum may look small or flat. Sometimes you can feel only one testicle, or none. Occasionally a testicle can be pushed back and forth between the groin and the scrotum, which makes the exam tricky. Your veterinarian is better at this than you are, so let them do the feeling.
Other signs are less obvious and tend to show up later:
- A retained testicle can twist on its own blood supply, which is painful and needs surgery.
- A retained testicle can develop a tumor, and some of these tumors release estrogen.
- Estrogen release can cause feminization, which may include a pendulous prepuce, enlarged mammary tissue, or attraction of other male dogs.
- In severe cases, estrogen effects can suppress the bone marrow [3].
A case report described a 7-month-old mixed-breed dog with a right retained testis who then developed swelling and hardening in the scrotum over three days [5]. The descended left testicle had twisted and died, and surgery removed both testicles [5]. That dog recovered well, but it shows how fast things can change [5].
If your dog is coughing or has other vague signs, those usually point to something else. See Dog Coughing: When Should You Worry? for that topic.
Causes and Risk Factors
Genetics is the biggest factor behind cryptorchidism, which is why the condition runs in families [2]. The exact inheritance pattern is not fully understood [1].
Breed matters too. German Shepherds, Siberian Huskies, Bulldogs and other flat-faced breeds, plus small breeds like Chihuahuas and Yorkshire Terriers, are more commonly affected [1].
Researchers have linked a few DNA variants to canine cryptorchidism, including changes in the RXFP2, HMGA2, and KAT6A genes [4]. Hormones such as INSL3 and testosterone, plus mechanical problems like a narrow inguinal canal or a short spermatic cord, are also thought to play a role [2]. Environmental and epigenetic factors may add to the picture, but this is still an active area of research [2].
One thing is clear. A retained testicle is not a cosmetic issue. It is a medical one.
How Veterinarians Diagnose a Retained Testicle
Diagnosis starts with a hands-on exam. Your veterinarian will palpate the scrotum and groin to see how many testicles they can find and where.
If the exam is unclear, imaging helps. Ultrasound is a safe, easy, and minimally invasive way to look for a testicle in the abdomen or groin [6]. Newer microvascular flow techniques can show tiny blood vessels in the testicle, which helps confirm what the tissue is [6].
Blood work may be part of the workup, especially if a tumor is suspected. Hormone testing for testosterone and estradiol, along with a testosterone-to-estradiol ratio, can support the diagnosis of an estrogen-producing tumor [3]. Preputial cytology, which samples cells from the sheath, can also show estrogen effects [3].
Your veterinarian will decide which tests your dog needs based on age, exam findings, and whether breeding is on the table.
Treatment Options
Neutering Is the Standard Treatment
The recommended treatment for cryptorchidism is neutering, which means surgical removal of both testicles [1]. Removing the retained testicle eliminates the cancer and torsion risk in that testicle. Removing the descended one prevents breeding and removes the source of most testosterone.
Surgery to find a retained testicle can be more involved than a routine neuter. An abdominal testicle may require opening the belly, while an inguinal one is often easier to reach. Your veterinarian will explain the plan for your dog.
What About Keeping One Testicle?
Unilateral surgery, meaning removal of only the retained testicle, may be considered when the other testicle looks normal on exam and ultrasound, and when preserving fertility or working ability is a priority [3]. This is a decision to make with your veterinarian, and it does not remove the genetic risk to future puppies.
Testicular Tumors
Testicular tumors are the most common tumors of the male reproductive tract in dogs, making up about 25% of all tumors in intact males [3]. The three main types are seminomas, interstitial Leydig cell tumors, and Sertoli cell tumors [3]. Sertoli cell tumors are the type most often seen in cryptorchid dogs [7].
Orchiectomy is the treatment of choice for most canine testicular cancers [3]. Many of these tumors cause problems through hormone production instead of spreading, but that does not make them harmless [3].
| Situation | What It Means | Typical Next Step |
|---|---|---|
| Both testicles down by 8 weeks | Normal descent | Routine puppy care |
| One testicle down, one missing | Unilateral cryptorchidism | Veterinary exam, plan neuter |
| Neither testicle down | Bilateral cryptorchidism | Veterinary exam, imaging, neuter |
| Retained testicle plus swelling or pain | Possible torsion or tumor | See a veterinarian promptly |
| Older intact male with mammary enlargement | Possible estrogen-producing tumor | Exam, ultrasound, blood work |
Recovery, Outlook, and Long-Term Management
Most dogs recover well after surgery to remove a retained testicle. The dog in the case report had no post-operative complications and was in good health at a follow-up visit about two and a half months later [5].
Expect a few days of rest, a cone or recovery suit if your dog licks, and a recheck with your veterinarian. Your clinic will give you specific instructions for incision care and activity limits.
Long term, a neutered dog no longer has the cancer risk that came with the retained testicle. That is the main win. If a tumor was already present, your veterinarian may want follow-up blood work to confirm hormone levels are returning to normal, especially if feminization or bone marrow effects were present [3].
If your dog was cryptorchid, tell your breeder and do not breed the dog or its close relatives [1]. That is how the condition gets passed down.
For broader questions about timing a neuter, see When to Neuter a Dog: Testosterone Cancer Risk Balance Guide.
Prevention
You cannot prevent cryptorchidism in a puppy that already has it. The testicle either descends or it does not.
What you can do is prevent it in the next generation. Because cryptorchidism is heritable, neutering affected dogs keeps the trait out of the gene pool [1]. If you are choosing a puppy, ask about the parents' history. If you are a breeder, do not repeat a pairing that produced a cryptorchid puppy.
Routine puppy exams are your best tool. Your veterinarian checks testicular descent at each visit, so a problem gets caught early.
If your dog has other health concerns, such as worms, see How Do I Know If My Dog's Got Worms or How To Tell If A Dog Has Roundworms Or Hookworms.
Limitations and When to Contact a Veterinarian
No article can tell you what is happening inside your specific dog. A hands-on exam and sometimes imaging are needed. Your veterinarian sets the plan for your pet.
Contact a veterinarian right away if you notice:
- Swelling, redness, or hardening in the scrotum, especially in a dog with a known retained testicle [5]
- Pain when you touch the groin or belly
- Vomiting, lethargy, or refusal to eat
- A sudden change in gait or reluctance to walk
- Enlarged mammary tissue or a pendulous prepuce in a male dog [3]
- Bleeding, bruising, or non-healing wounds
Call your veterinarian the same day for scrotal swelling or pain. Go to an emergency clinic now if your dog is collapsed, has a swollen painful abdomen, or is straining to breathe. Schedule a routine visit if you cannot feel two testicles in your puppy by 8 weeks, or if you have an older intact male who has never been checked.
Frequently Asked Questions
Can a retained testicle drop on its own later?
It can in some puppies, which is why many veterinarians wait until about 16 weeks before making a final call [2]. After that window, spontaneous descent is unlikely. If your puppy is past 16 weeks and you still cannot feel both testicles, plan for a veterinary exam.
Is cryptorchidism painful for my dog?
Usually not by itself. A retained testicle sitting quietly in the belly or groin often causes no obvious pain. Pain shows up when the testicle twists or a tumor grows, which is why monitoring matters.
Does neutering fix the cancer risk?
Neutering removes the retained testicle, so it removes the cancer risk in that testicle [1]. It also removes the descended testicle, which eliminates the source of most testosterone and prevents breeding. This is why neutering is the recommended treatment [1].
Can a cryptorchid dog still father puppies?
Yes, if one testicle is descended and healthy, the dog can still breed and pass on the trait [1]. That is one reason neutering is recommended. It protects future generations from inheriting the condition.
Which breeds are most at risk?
German Shepherds, Siberian Huskies, Bulldogs and other flat-faced breeds, Chihuahuas, and Yorkshire Terriers are more commonly affected [1]. Genetics is the most significant factor overall [2]. If you have one of these breeds, watch testicular descent closely during puppy visits.
If your dog ate something unusual during all this, see Dog Ate a Toy: When to Worry and What to Do.
Related Articles
- Dog Coughing: When Should You Worry?
- How Do I Know If My Dog's Got Worms
- Dog Ate a Toy: When to Worry and What to Do
- How To Tell If A Dog Has Roundworms Or Hookworms
- When to Neuter a Dog: Testosterone Cancer Risk Balance Guide
- Dog Not Eating: When to Worry and What to Do
- Lump on Your Dog's Testicle or Genital Area
- When Do Dogs Come Out of Adolescence?
- Puppy Umbilical Cord: Care and When It Falls Off
References
- Cryptorchidism in dogs (retained testicle). Cornell University College of Veterinary Medicine.
- Laterality and Breed Distribution of Cryptorchidism in 251 Dogs: A Retrospective Clinical Study. Veterinary sciences, 2026.
- Clinical Management of Testicular Tumors in Dogs. Animals : an open access journal from MDPI, 2026.
- Exploring Testicular Descent: Recent Findings and Future Prospects in Canine Cryptorchidism. Sexual development : genetics, molecular biology, evolution, endocrinology, embryology, and pathology of sex determination and differentiation, 2024.
- Right-sided cryptorchidism and contralateral intrascrotal testicular torsion in a young dog: a rare case report. Veterinary research communications, 2025.
- Testicular vascularization in healthy dogs using a microvascular flow imaging technique - MicroV. Brazilian journal of veterinary medicine, 2026.
- Cryptorchidism and testicular cancer in the dog: unresolved questions and challenges in translating insights from human studies†. Biology of reproduction, 2024.