l Written by Seoul Asan S Urology Clinic
l Edited by Sia, The Pylon Square
While bathing your baby or changing a diaper, you may notice that one side of the scrotum looks smaller than the other, or that you cannot easily feel a testicle.
Newborns and young children are small, so it is often hard for parents to tell what is going on. One condition worth checking in this situation is an undescended testicle, also known as cryptorchidism.
Not every undescended testicle needs surgery right away. A testicle may descend on its own during the first 6 months of life (corrected age for premature babies).
If it has not descended by then, a pediatric urology specialist can confirm the diagnosis and plan surgery, known as orchiopexy.
Surgery is generally recommended between 6 and 12 months of age and should be completed by 18 months at the latest.
What Is an Undescended Testicle?

An undescended testicle occurs when a testicle that forms in the abdomen during pregnancy does not move down to its normal position in the scrotum, before or after birth.
Normally, the testicles move down into the scrotum late in pregnancy. If various factors prevent this movement from being completed, an undescended testicle can occur. It can affect one side or both.
What Causes an Undescended Testicle?
No single cause explains every case. Several factors may work together, including:
- Changes during fetal growth
- Problems with the testicle's movement
- Hormonal influences
- Genetic factors
- Premature birth or low birth weight
In many cases, the exact cause cannot be identified. It has nothing to do with anything you did or did not do as a parent.
Why Treatment Timing Matters
If a testicle stays outside the scrotum, it may affect how the testicle develops and your child’s future fertility. Undescended testicles are also linked to a higher risk of testicular cancer later in life. That is why timely treatment and continued monitoring are important.
Surgery is generally recommended between 6 and 12 months of age and should be completed by 18 months at the latest.
Treatment and Surgery

A testicle that cannot be felt in the scrotum is not always an undescended testicle.
One condition doctors need to distinguish is a retractile testicle. A muscle reflex temporarily pulls the testicle up toward the groin, and it later returns to the scrotum.
An ascending testicle, which could once be felt in the scrotum but moves higher as a child grows, also needs to be checked.
Treatment can differ across these three conditions, so an accurate examination should guide the next steps.
How Is It Diagnosed?
Diagnosis centers on a physical examination by a specialist. Ultrasound or hormone tests are considered only when the specialist finds them necessary for your child.
- Physical examination: Checks whether the testicle can be felt and helps distinguish a retractile testicle from a true undescended testicle
- Ultrasound: Helps locate a testicle in the groin or abdomen
- Hormone tests: Assess testicular function and check for endocrine problems
Surgical Options
Once an undescended testicle is confirmed, the surgical approach may vary according to its position. The main options are:
- Laparoscopic orchiopexy: A minimally invasive approach for a testicle inside the abdomen. The surgeon locates it through small incisions, then secures it in the scrotum.
- Open orchiopexy: Used mainly when the testicle can be felt. The surgeon reaches it through an incision in the groin or scrotum, then secures it in place.
Choosing a Pediatric Urology Clinic
When choosing a clinic for your child, these points are helpful to check:
- Experience in pediatric urology
- A careful physical examination and clear consultation
- A treatment plan that considers your child's growth
- A system for follow-up care after surgery
Above all, look for a clinic that understands your concerns and examines your child carefully.
Where to Start in Korea: Seoul Asan S Urology Clinic
Seoul Asan S Urology Clinic provides accurate diagnosis and surgery for undescended testicles in children, along with treatment for conditions such as buried penis and hydrocele. Dr. Song Sang-hoon, a former professor at Asan Medical Center and Secretary General of the Korean Society of Pediatric Urology, personally leads consultations and surgery.
On-site English, Russian, and Chinese coordinators support international families. If you are looking for a trusted pediatric urology clinic in Korea, our concierge team can help arrange your consultation.
⇒ Book at Seoul Asan S Urology Clinic
Frequently Asked Questions
Q1. At what age should an undescended testicle be treated?
See a specialist if the testicle has not descended by 6 months of age, or 6 months corrected age for premature babies. Surgery is generally recommended between 6 and 12 months of age and should be completed by 18 months at the latest. Even if this window has passed, please seek care as soon as you can.
Q2. My son's testicle comes and goes. Is it undescended or retractile?
It may be a retractile testicle, but a specialist needs to examine him to confirm this. A retractile testicle usually needs regular monitoring rather than treatment. Because a testicle that was once in the scrotum can also move higher over time, an examination is still important.
Q3. Can hormones treat an undescended testicle instead of surgery?
Usually not. Orchiopexy is the standard treatment. The American Urological Association (AUA) does not recommend hormone therapy, and the European Association of Urology (EAU) finds no benefit for future paternity from hormone therapy for a single undescended testicle.
Q4. Does undescended testicle surgery remove the risk of infertility or cancer?
Not completely. Timely surgery can help lower these risks, but it cannot prevent long-term problems in every case. Regular checkups are still needed after surgery, and it is helpful to learn self-examination after puberty.
Q5. If we travel to Korea for surgery, how soon can my child fly home after orchiopexy?
There is no single timeline, so your child’s doctor will decide based on the surgical method and his recovery. Being ready for discharge does not automatically mean he is ready for a long-haul flight, and a follow-up visit is usually recommended after surgery.
Before you book your return flight, The Pylon Square can help you confirm the timing with the clinic and plan your stay.