Many men wonder about the size of their testicles and whether their size is normal. While size can be a concern, it’s more important that your testicles are functioning properly. What’s considered a normal size varies a lot depending on your age and stage of development.
Knowing the normal size of testis according to age in cm is important because a noticeable change or deviation from local norms could point to an underlying health issue. For instance, having unusually small testicles could indicate hypogonadism or Klinefelter syndrome.
In this article, we’ll cover:
- testicular anatomy
- testicular function
- testicular development
- normal testicular size variations
- potential causes of size abnormalities
- available medical interventions
Testicular Anatomy and Function
Let’s dive into the details of testicular anatomy and function.
Basic Anatomy
The testicles, also called testes, are oval-shaped organs. They’re located inside the scrotum, which hangs below the penis. In adults, the testicles typically weigh about 20 grams. It’s normal for one testicle to be a bit bigger than the other.
The testicles are made up of several key components:
- Tunica albuginea: A tough, fibrous capsule that surrounds and protects the testicle.
- Seminiferous tubules: Coiled tubes where sperm production takes place. Each testis contains 250 to 400 lobules, and each lobule contains 2-3 seminiferous tubules.
- Epididymis: A coiled tube located on the back of the testicle where sperm mature and are stored.
- Vas deferens: A tube that transports sperm from the epididymis to the ejaculatory ducts.
Key Functions
The testicles have two main jobs:
- Sperm production (spermatogenesis): The seminiferous tubules are responsible for producing sperm, the male reproductive cells.
- Testosterone production (hormone synthesis): The testicles produce testosterone, the primary male sex hormone.
Testosterone plays a crucial role in the development of male secondary sexual characteristics, such as facial hair, a deeper voice, and increased muscle mass, though some may be concerned about a high testosterone and hair loss link. It also influences bone density and libido.
Testicular Development and Growth: Tanner Stages
Testicular size changes throughout a person’s life, particularly during puberty. Doctors use the Tanner scale to assess the physical development of children and teens as they go through puberty. Here’s what you can expect at each stage:
Childhood and Early Puberty
During childhood, the testicles are quite small. You’ll typically see a testicular volume of just 1–3 ml. At 1 year old, the testicular length is usually around 1.3 cm.
As puberty begins, the testicles start to grow. In early puberty, the volume increases to 4–6 ml. There’s also a gradual increase in testicular length.
Mid to Late Puberty
The testicles grow more rapidly during mid-puberty, typically around ages 9 or 10. At this stage, the volume is about 8–10 ml.
In late puberty, the testicles continue to develop, reaching a volume of 14–16 ml. This stage correlates with sexual maturity rating (SMR), indicating further development of secondary sexual characteristics.
Adulthood
Adult testicular volume typically ranges from 18–25 ml. By the time a person reaches 18 years old, the testicular length is around 4.4 cm.
It’s worth noting that there can be variations in adult size. On average, testicle size ranges from 3.6 to 5.5 cm in length and 2.1 to 3.5 cm in width. Adult testes typically measure 3–5 cm in length and 2–3 cm in width, with a volume of 12.5–19 mL.
Normative Testicular Size Data by Age
Testicle size varies a lot from person to person, and it also changes as you age. Here’s a general overview of what’s considered normal at different life stages:
Infancy to Pre-Puberty (0-9 years)
During infancy and early childhood, testicles are relatively small. At 1 year old, the average testicular volume is around 1.8 ± 0.5 ml, with a length of about 1.3 ± 0.4 cm. There’s a gradual increase as kids get older.
It’s important for doctors to monitor the growth of testicles during these early years to catch any potential developmental delays. Doctors often compare measurements against local norms and growth charts.
Puberty (10-18 years)
Puberty is when things really start to change. At 10 years old, the average testicular volume is around 3.3 ± 1.2 ml, with a length of about 2.1 ± 0.5 cm. You’ll see a pretty significant increase around ages 9-10. Doctors use age-specific Z-scores to track testicular volume and length during this time.
Testicular growth is closely linked to the Tanner stages of sexual maturity. The Tanner stages give doctors a reference for average testicle size at different ages during puberty. There’s even a formula some doctors use to estimate testicular volume based on length: Testicular volume = −7.5 + 6.3 × testicular length.
Adulthood (18+ years)
In adulthood, the normal range for testicular volume is about 12.5-19 ml. A common way to describe the average size is around 4 x 3 x 2 cm. Keep in mind that there’s a lot of variation, and it’s totally normal for one testicle to be slightly smaller than the other.
It’s also important to remember that size isn’t the main thing that determines fertility, factors like sperm volume also play a crucial role. Healthy “plumbing,” meaning the tubes and structures that carry sperm, is way more crucial.
Measuring Testicular Size: Methods and Considerations
So, how do doctors determine testicular size? There are a few different methods, each with its own pros and cons.
Physical Examination
The simplest way is through a physical exam. Doctors will gently feel (palpate) the testicles and visually estimate their size. They’ll also use a tape measure to get a more precise measurement.
During the exam, they’re not just looking at size. They’re also checking for consistency (are they firm but not too hard?), tenderness (is there any pain?), and any other unusual lumps or bumps. It’s worth noting that performing self-exams after a warm bath or shower can make things easier, as the scrotal skin is more relaxed.
Orchidometer
Another method involves using an orchidometer, specifically the Prader Orchidometer. This tool consists of a series of ellipsoid-shaped beads of varying sizes. The doctor compares the patient’s testicle to these beads to find the closest match in volume.
An orchidometer offers a more accurate volume estimate than simple palpation. However, it does require some training and experience to use correctly.
Imaging Techniques
In some cases, doctors might use imaging techniques like ultrasound or MRI to assess testicular size and identify any underlying abnormalities. Ultrasound is a common and readily available option, while MRI can provide even more detailed anatomical information.
These techniques are particularly useful for detecting masses, cysts, or other structural problems within the testicles.
Factors Influencing Testicular Size: Health and Lifestyle
Testicular size isn’t fixed, and a number of factors can influence it. Some are related to underlying health conditions, while others relate to lifestyle and environment.
Medical Conditions
Certain medical conditions can have a direct impact on testicular size:
- Hypogonadism: This condition, characterized by low testosterone levels, can lead to smaller testicles. Low T can affect many aspects of a man’s health, including sexual function and muscle mass.
- Klinefelter Syndrome: This genetic condition, where a male has an extra X chromosome (XXY instead of XY), often results in smaller testicles, reduced sperm production, and lower testosterone levels.
- Testicular Atrophy: Several factors can cause the testicles to shrink (atrophy). These include sexually transmitted infections (STIs), trauma or injury to the testicles, and testicular torsion (a twisting of the spermatic cord that cuts off blood supply).
Lifestyle Factors
Your daily habits and environment can also play a role:
- Temperature: Testicle size can fluctuate depending on the temperature. They may appear smaller in colder environments and larger in warmer ones. This is a natural physiological response to help regulate sperm production.
- Age: As men age, it’s normal for the testicles to decrease in size (atrophy) to some degree. This is a natural part of the aging process.
Other Influences
Beyond medical and lifestyle factors, there are other interesting connections:
- Sperm Production: Some research suggests a possible link between testicular size and sperm production. Larger testicles may correlate with higher sperm counts, but this isn’t a definitive rule.
- Psychological Aspects: Men can have aesthetic concerns related to the size of their testicles. Interestingly, a 2013 study suggested that men with slightly smaller testicles might exhibit more nurturing parenting styles.
Frequently Asked Questions
What is the “best” testicle size?
There’s no single “best” size for testicles. Size varies naturally between individuals and throughout life. Doctors are typically more concerned with changes in size, consistency, or any associated pain, rather than absolute measurements.
What is inside a testicle?
Each testicle contains tightly coiled tubes called seminiferous tubules, where sperm production occurs. They also house Leydig cells, which produce testosterone, and Sertoli cells, which support sperm development. The epididymis, located on the back of the testicle, stores and matures sperm.
What is special about the left testicle?
It’s common for one testicle, usually the left, to hang slightly lower than the other. This is due to anatomical differences in the spermatic cord, which supplies blood to the testicles. It’s generally not a cause for concern unless accompanied by pain or other symptoms.
How to measure testicle size at home?
While not a substitute for a medical exam, you can estimate testicle size at home by gently feeling them and comparing them to common objects like grapes, olives, or walnuts. Note any changes in size or texture and discuss them with your doctor.
What is the “ruler” for testicle size?
Doctors use a tool called an orchidometer to measure testicle volume. It consists of a series of ellipsoid beads of increasing sizes, which are compared to the patient’s testicles to estimate volume. This isn’t something typically used at home.
Final Thoughts
Testicle size changes as you go through life. The biggest growth spurt happens during puberty. For most men, testicles will measure between 3.6 and 5.5 cm long and 2.1 and 3.5 cm wide.
What’s most important is that you get familiar with the way your testicles look and feel. Regular self-exams can help you catch any changes early, which is especially important for finding cancer when it’s most treatable. If you’re worried about the size of your testicles, a doctor or urologist can give you personalized advice.
In the end, remember that size isn’t everything. As long as your “plumbing” is working well, the size of your testicles isn’t the main thing that determines your health or fertility.