Checking for an undescended testicle starts with a simple visual and physical exam of the scrotum. In most cases, you can tell by gently feeling whether a testicle is present on each side. About 1.1% of full-term male newborns have an undescended testicle at birth, and that number jumps to nearly 12% in premature boys. Most cases resolve on their own within the first few months of life, but knowing how to check (and what you’re feeling for) helps you catch the ones that don’t.
What You’re Looking For
A normal scrotum has two testicles, one on each side, that you can see or feel as small, smooth, oval-shaped lumps. An undescended testicle is one that never made it down into the scrotum during development. It may be sitting somewhere along the path between the abdomen and the groin, or in rarer cases, it may have traveled to an unexpected location entirely, such as the inner thigh, the perineum, or the lower abdominal wall.
When one side of the scrotum looks flatter or smaller than the other, or when you can only feel one testicle instead of two, that’s the main sign. In some cases, neither testicle is palpable.
How to Do a Physical Check
The best time to check an infant is during a warm bath or right after one. Warmth relaxes the muscles around the scrotum, which makes the testicles easier to locate. Cold air, a cold hand, or even touching the inner thigh can trigger a reflex that pulls the testicles upward temporarily, making the exam unreliable.
With warm, clean hands, gently feel each side of the scrotum between your thumb and fingers. You should be able to feel a small, firm, oval shape on each side. If one side feels empty, slowly run your fingertips along the crease where the thigh meets the groin (the inguinal canal). An undescended testicle is often sitting somewhere along this path. If you feel a small lump there, try gently guiding it downward toward the scrotum. Pay attention to what happens when you let go.
If the testicle slides back up immediately once you release it and won’t stay in the scrotum without constant pressure, that’s consistent with a true undescended testicle. If it stays in place on its own after you guide it down, you’re likely dealing with something different: a retractile testicle.
Retractile vs. Truly Undescended
This distinction matters because the two conditions have very different outlooks. A retractile testicle has fully descended into the scrotum but moves back up into the groin as a reflex response to touch, temperature changes, fear, or even laughter. This reflex is extremely common in infants and young children. The key test: if you can gently coax the testicle into the scrotum and it stays there without tension, it’s retractile. Retractile testicles don’t cause complications and don’t raise cancer risk.
A truly undescended testicle, by contrast, either can’t be moved into the scrotum at all or immediately retracts the moment you stop holding it in place. It may sit in the inguinal canal, higher up in the abdomen, or in an ectopic location outside the normal path of descent. This is the type that needs medical evaluation.
Checking Older Children and Adults
Doctors check for undescended testicles at birth and at every well-child visit throughout childhood. But a condition called “acquired undescended testicle” can develop later, where a testicle that was previously in the scrotum ascends over time. This is why ongoing checks matter.
For older boys and teens, the same basic approach applies. Have the child stand in a warm room. Visually compare both sides of the scrotum for symmetry, then gently palpate each side. If you notice one side consistently feels empty, especially during routine checks over several weeks, bring it up with a pediatrician. Adults checking themselves follow the same principle: if you can’t feel a testicle on one side, or if one side of the scrotum has always appeared underdeveloped, it’s worth getting evaluated.
When the Testicle Can’t Be Found at All
In some cases, no amount of careful palpation reveals a testicle on the affected side. This is called a nonpalpable undescended testicle, and it means the testicle may be sitting deep in the abdomen where it can’t be felt through the skin. You might expect an ultrasound to help locate it, but current urology guidelines actually advise against relying on imaging for nonpalpable testicles. Ultrasound isn’t reliable enough at finding testicles hidden in the abdomen, and a negative result doesn’t rule anything out. Instead, specialists typically use a minimally invasive surgical procedure to visually locate and assess the testicle directly.
The Timeline for Spontaneous Descent
If a testicle is undescended at birth, the odds are in your favor for the first few months. Most undescended testicles drop into the scrotum on their own within three to six months of life. By six months of age, fewer than 1% of boys still have the condition. After six months, spontaneous descent becomes unlikely.
Current guidelines from the American Urological Association recommend referral to a surgical specialist if the testicle hasn’t descended by six months of age (adjusted for prematurity). Surgery should happen within the following year, ideally before 18 months of age, to give the best chance of preserving future fertility.
Why Early Detection Matters
An undescended testicle that stays outside the scrotum long-term faces two main risks. The first is reduced fertility. The scrotum keeps testicles slightly cooler than core body temperature, which is essential for healthy sperm production. A testicle left in the warmer environment of the abdomen or groin gradually loses its ability to produce sperm. Surgery before 18 months significantly improves the chances of preserving that function, especially in boys where both testicles are affected.
The second risk is testicular cancer later in life. An undescended testicle carries a higher cancer risk than one that descended normally, and this elevated risk persists even after surgical correction, though early surgery reduces it. This is why boys and men with a history of an undescended testicle are encouraged to be familiar with how their testicles normally feel, so they can notice changes over time.
What to Watch For at Home
If you’re a parent checking your infant, the most practical approach is to make it part of bath time. Every few weeks during a warm bath, gently feel both sides of the scrotum. You’re looking for consistency: is the same testicle always absent, or does it come and go? A testicle that’s sometimes present and sometimes not is likely retractile. One that’s never in the scrotum is the one that needs attention.
Keep in mind that the scrotum in newborns and infants is small, and testicles can be surprisingly hard to pin down even when everything is normal. If you’re unsure about what you’re feeling, your pediatrician performs this exact check at routine visits and can quickly tell you whether there’s a concern.