For most males, the testicles descend into the scrotum before birth, not during puberty. If you can feel two small, oval-shaped masses sitting inside your scrotum, your testicles have dropped. The phrase “balls dropping” gets mixed up with puberty, but descent and puberty are two separate events.
What “Dropping” Actually Means
During fetal development, the testicles form near the kidneys inside the abdomen. They begin migrating downward around the eighth week of pregnancy. By roughly the 33rd week of gestation, both testicles have typically traveled through the abdominal wall, through the groin (inguinal canal), and into the scrotum. This journey is complete before a full-term baby is born.
About 3% of full-term male infants are born with one or both testicles still undescended. For premature babies, that number jumps to around 30%, simply because the testicles hadn’t finished their journey when birth happened early. In most of these cases, the testicles finish descending on their own within the first three months of life, bringing the true rate of persistent undescended testicles down to about 1%.
Why People Confuse This With Puberty
The confusion makes sense. During puberty, the testicles grow dramatically, the scrotum gets larger and darker, and the voice deepens. It feels like something “dropped.” But what’s actually happening is rapid growth, not descent. Before puberty, each testicle is tiny, less than 1.3 centimeters wide and barely over 1 milliliter in volume. Once puberty starts (typically between ages 10 and 14), the testicles begin to enlarge. By the end of puberty they can reach 15 to 21 milliliters, roughly 15 times their prepubertal size. That dramatic increase in size and weight makes the scrotum hang noticeably lower, which is probably where the idea of “dropping” during puberty comes from.
So if you’re a teenager wondering whether your balls have dropped, the real question is likely one of two things: either you’re noticing normal pubertal growth (which varies in timing from person to person), or you’re concerned that a testicle might actually be missing from your scrotum.
How to Check
The simplest way to tell is by feel. Stand up, and with clean hands, gently feel your scrotum. You should be able to identify two separate oval-shaped masses, one on each side. Each one should feel firm but slightly spongy, similar to a peeled hard-boiled egg. If you can feel both, your testicles have descended normally.
If one side of the scrotum feels empty or noticeably flatter than the other, that testicle may not have descended fully. A warm bath or shower can help, because warmth relaxes the muscles that pull the testicles upward, making them easier to locate.
Retractile Testicles vs. Undescended Testicles
Sometimes a testicle seems to disappear and reappear. This is called a retractile testicle, and it’s different from a truly undescended one. A muscle called the cremaster wraps around each testicle like a pouch. When this muscle contracts (from cold temperatures, touch, or anxiety), it can pull a testicle up out of the scrotum and into the groin. If the reflex is particularly strong, the testicle may spend a lot of time retracted.
The key difference: a retractile testicle originally descended normally and can be gently guided back into the scrotum by hand, where it stays temporarily before the muscle pulls it back up again. A truly undescended testicle never made it into the scrotum in the first place and can’t be moved there manually. Retractile testicles are generally harmless and often resolve on their own by the end of puberty as the testicle grows too large for the muscle to pull it back up.
There’s also a third category called an ascending testicle. This is one that descended normally early in life but has since moved back up into the groin and won’t stay in the scrotum even when guided by hand. This type can require medical attention.
Why It Matters if a Testicle Never Descended
Testicles need to be in the scrotum because the scrotum keeps them a few degrees cooler than core body temperature. That temperature difference is essential for healthy sperm production. When a testicle stays inside the body, the excess heat gradually damages the tissue responsible for making sperm.
Men with a history of both testicles being undescended face a sixfold increased risk of infertility compared to the general male population, where infertility affects only 1% to 2% of men. The risk of testicular cancer also rises. Men with a history of an undescended testicle have roughly a 3% lifetime risk of testicular cancer, which is 5 to 10 times higher than average. When corrective surgery is performed before age 13, that cancer risk drops to about 2%. If surgery happens after 13 or not at all, the risk climbs to around 5%.
When Surgery Is Recommended
Current guidelines from the American Urological Association recommend that if a baby’s testicle hasn’t descended on its own by six months of age (adjusted for prematurity), the infant should be referred to a surgeon. The procedure, called orchiopexy, involves moving the testicle into the scrotum and securing it in place. It’s ideally performed before 18 months of age to give the best chance of preserving fertility.
For older children, teens, or adults who discover a testicle is undescended or has ascended, the same surgery can still be performed. The benefits decrease with age, but it still reduces cancer risk and allows for easier monitoring of the testicle going forward, since a testicle trapped in the groin or abdomen can’t be checked during a routine self-exam.
Signs That Puberty Is Progressing Normally
If your real concern is whether puberty is happening on schedule, testicular growth is actually the first sign, often appearing before any other changes. The earliest stage of puberty involves the testicles widening from under 1.3 cm to about 1.5 to 2.1 cm. This typically happens between ages 10 and 15. You probably won’t notice this change by looking in the mirror, but you may notice that the scrotum starts to look different: the skin gets thinner, redder or darker, and hangs lower.
After testicular growth begins, pubic hair, a growth spurt, and voice changes follow over the next few years. The testicles continue growing throughout puberty, reaching adult size (2.5 to 3.1 cm wide) by roughly ages 13 to 17. If you’re 14 or older and haven’t noticed any of these changes, that’s worth mentioning to a doctor, as it could indicate delayed puberty, which is usually treatable and often just a matter of timing.