Many boys wonder when their testicles will drop during puberty. This is a common question as the descent of the testes is one of the major physical changes that occur during male adolescence.
What is Testicular Descent?
Testicular descent, also called cryptorchidism, is the process by which the testes move from the abdomen into the scrotum during fetal development. In most boys, both testicles have descended by the time they are born. In some cases, descent may not be complete until a few months after birth.
The testes develop inside the abdomen near the kidneys during early fetal development. Towards the end of pregnancy, hormones signal for the testicles to descend into the scrotal sac. This is important for sperm development and fertility later in life.
By 6 months of age, over 90% of boys have complete testicular descent. If the testes do not descend fully by 1 year of age, it is considered a condition called undescended testicles or cryptorchidism, which may require treatment.
When Do Testicles Drop During Puberty?
Testicular descent from the abdomen to the scrotum is complete long before puberty starts for most boys. The testicles are already within the scrotum at birth or descend within the first year of life.
However, the scrotum and testicles do increase in size and develop further during puberty. This is due to the influence of hormones such as testosterone.
Here are some of the normal changes that happen to the testes during male puberty:
- The scrotum darkens in color and hangs lower behind the penis.
- The testicular volume increases as the seminiferous tubules grow and sperm production begins.
- The testicles grow larger and become oval shaped rather than round.
These changes often start between the ages of 9-14 years. Testicular growth tends to accelerate around 13-14 years of age. The testicles reach their adult size by around age 16-17, at the end of puberty.
Signs That Testicles Are Descending During Puberty
Since testicular descent occurs before birth or during infancy for most boys, there are no signs to watch for during puberty. But, there are some changes parents and boys may notice in the scrotum and testicles during adolescence:
- Scrotum darkening – the scrotal sac darkens and reddens in color as it grows.
- Scrotum Growth – the scrotum enlarges and elongates as the testicles grow larger inside.
- Testicular volume increase – Feelable increase in the size and weight of testicles within the scrotum.
- Scrotum hangs lower – the scrotum elongates and hangs lower behind the penis as the cremaster muscle relaxes.
- Changed shape – testicles become more oval shaped rather than round as they mature.
- More visible veins – veins along the scrotum become more visible as the scrotal skin thins out.
These gradual changes are normal during testicular development in puberty. Tracking testicular growth on a graph is one way some pediatricians monitor puberty progression.
Does Late Testicular Descent Occur?
It is very rare for testicular descent to occur as late as age 15. By one year of age, over 90 percent of boys have complete testicular descent. Late descent at 15 years old would be considered abnormal.
However, there are some rare cases where testicles may abnormally retract back up into the lower abdomen later in childhood. This is called acquired cryptorchidism or ascending testes. It usually requires surgery to reposition the testicles.
What Causes Late Testicular Descent?
True late testicular descent at age 15 is uncommon. Possible reasons for abnormally late descent include:
- Low hormone levels – low testosterone or other hormone imbalance affecting genital development.
- Anatomical defects – abnormalities of the genital tract that prevent normal descent.
- Retractile testes – testicles that can abnormally retract into the abdomen.
- Acquired cryptorchidism – testicular ascent after completing normal infant descent.
- Undervirilization disorders – diseases/syndromes that affect genital development.
Any boy who has not experienced testicular descent by 13-14 years old should be evaluated by a pediatrician. Hormone tests and imaging studies may be recommended to look for underlying problems.
Treatment for Late Descent of Testicles
Treatment depends on the cause of delayed testicular descent at puberty:
- Hormone therapy – testosterone supplements if hormone deficiency is causing delayed puberty.
- Surgery – orchiopexy or orchidopexy to relocate abnormally positioned testicles into the scrotum.
- Other medical care – treatment of associated problems like hypogonadism, retractile testes, or anatomical abnormalities preventing descent.
Without treatment, late testicular descent can result in problems like infertility or testicular cancer later in life. Therefore, it needs proper evaluation and management.
What is Normal Age for Testicles to Drop?
Here is a summary of the normal timeline for testicular descent:
- By 16 weeks gestation – testes descend to inguinal canal
- 26-28 weeks gestation – testes travel through inguinal canal
- By 35 weeks gestation – testes finish descent into scrotum
- Full descent by 3-6 months of age for most infants
- Over 90% testicular descent by 6 months old
- Full descent by 1 year old for nearly all boys
If testicles have not fully descended by one year of age, further evaluation for cryptorchidism is recommended. Descent and growth of the testicles continues through puberty, but descent itself is complete before adolescence.
Testicular Descent in Weeks Gestation
| Gestational Age | Testicular Position |
|---|---|
| 16 weeks | Descend to inguinal canal |
| 26-28 weeks | Pass through inguinal canal |
| 35 weeks | Finish descent into scrotum |
Is Delayed Puberty Associated with Late Testicular Descent?
Yes, delayed onset of puberty can be associated with late testicular descent. Puberty is initiated by a complex cascade of hormonal changes. Low levels of hormones like testosterone, LH, and FSH can delay pubertal development.
Some reasons delayed puberty is associated with late testicular descent:
- Hypogonadism – low testosterone due to problems with testes or pituitary gland
- Kallmann syndrome – delayed puberty and lack of testicular descent due to low GnRH levels.
- Pituitary tumors – abnormalities in the pituitary gland disrupting hormonal signals.
- Genetic disorders – diseases/syndromes that affect gonadal and genital development.
Evaluation of delayed puberty involves testing levels of gonadotropins and sex hormones. This helps identify any hormone deficiencies or endocrine abnormalities causing delayed development.
Should I Worry if My Son’s Testicles Haven’t Dropped by Age 15?
Yes, lack of testicular descent by 15 years old is a concern requiring medical evaluation. The most common reasons to worry include:
- Fertility problems – increased risk of infertility later in life without treatment.
- Testicular cancer risk – undescended testes have higher risk of developing testicular cancer.
- Underlying disorder – may reflect an undiagnosed hormone deficiency, genetic syndrome, or anatomical defect.
- Psychosocial effects – delayed puberty can affect self-esteem and social development.
See a pediatrician promptly if your son has not exhibited testicular growth and descent by 13-14 years old. Further testing and treatment is crucial to get delayed puberty back on track and prevent future health problems.
Takeaway Messages
- Testicular descent into the scrotum occurs before birth or within the first year after birth for most boys.
- The scrotum and testes continue to grow and develop during puberty due to hormonal influences.
- True testicular descent at 15 years old is very abnormal and concerning for underlying disorders.
- Delayed puberty can be associated with impaired testicular descent due to hormone deficiencies.
- Evaluation and treatment by a pediatrician is recommended if no testicular enlargement and descent occurs by 13-14 years old.