Table of ContentsView AllTable of ContentsAnatomyFunctionCongenital ConditionsMedical ConditionsDiagnosis
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View All
Table of Contents
Anatomy
Function
Congenital Conditions
Medical Conditions
Diagnosis
The testes, or testicles, are two egg-shaped sex organs that play an important role in the male reproductive system. The testes are wheresperm cellsare produced and are also responsible for the production of the sex hormonetestosterone.
The testes are housed in a pouch of skin beneath thepeniscalled thescrotum. Their location outside the abdomen ensures that the testes remain at the ideal temperature for sperm cells to develop. Although the testes can produce sperm and testosterone throughout a person’s lifetime, they are vulnerable to injury can medical conditions that can causeinfertility.
PIXOLOGICSTUDIO/SCIENCE PHOTO LIBRARY / Getty Images
A Note on Gender and Sex TerminologyTestes are found in people born with a penis, who are typically assigned male at birth.Verywell Health acknowledges thatsex and genderare related concepts, but they are not the same. To accurately reflect our sources, this article uses terms like “male," “man,” and “female” as the sources use them.
A Note on Gender and Sex Terminology
Testes are found in people born with a penis, who are typically assigned male at birth.Verywell Health acknowledges thatsex and genderare related concepts, but they are not the same. To accurately reflect our sources, this article uses terms like “male," “man,” and “female” as the sources use them.
Testes are found in people born with a penis, who are typically assigned male at birth.
Verywell Health acknowledges thatsex and genderare related concepts, but they are not the same. To accurately reflect our sources, this article uses terms like “male," “man,” and “female” as the sources use them.
Anatomy of the Testes
Most males are born with two testes (testicles). These are soft, egg-shaped organs located inside the scrotum. One testicle is referred to as atestis.
The testes are made up of several lobes that contain a network of narrow tubes calledseminiferous tubules. These are wherespermare produced in a process known asspermatogenesis. Situated between seminiferous tubules areLeydig cellsthat secrete testosterone crucial to the development of sperm cells.
As the sperm cells start to mature, they move through these tubules until they reach a wider conduit called therete testes.
The immature cells are then passed to a tightly coiled tube on the outside of each testicle called theepididymis. This is where sperm cells are stored and complete maturation.
In adult males, the testes are around 2 to 3 centimeters wide and roughly 3 to 5 centimeters long. The testes increase in size through adulthood and then decrease in size later in life due to the natural decline in testosterone.
Function of the Testes
The testes have two primary functions: the production of testosterone and the creation of mature sperm cells.
Production of Testosterone
Spermatogenesis
The second function of the testes is to produce sperm. Spermatogenesis is a continuous, life-long process that occurs in three steps:
Unlike females, who only produce a limited number of eggs over a lifetime, males can produce millions of sperm each day. It then takes several months for the sperm cells to mature enough to be functional. The maturation starts in the testes but mostly takes place inside the epididymis.
Without ample testosterone, sperm cells cannot mature as they should, resulting in infertility.
How Long Sperm Lives Inside and Outside of the Body
There are a number ofcongenital conditionsthat can affect either the location or appearance of a testicle. Congenital conditions are those that occur during fetal development.
Cryptorchidism
Cryptorchidismis a condition where one or both testicles have not moved into the scrotum prior to birth. Also known as an undescended testicle, it is one of the most common congenital conditions affecting male babies.
Cryptorchidism in infants is not considered a medical emergency, and the testicle will often descend on its own without treatment.
If the testicle has not descended within the first few months, a surgical procedure known asorchiopexymay be used to repair the abnormality. This is because cryptorchidism can expose the testicle to higher body temperatures within the abdomen, increasing the risk of infertility andtesticular cancer.
Retractile testis is a similar condition in which a testicle moves back and forth from the scrotum to the abdomen. As long as the testes spend most of their time in the scrotum, it is not considered as problematic as undescended testes and may not require treatment.
Polyorchidism
When a person is born with more than two testicles, the condition is referred to aspolyorchidism. People with polyorchidism most commonly have three testicles but can have as many as five. It is a very rare condition with fewer than 200 reported cases.
Transverse Testicular Ectopia
Transverse testicular ectopia, or crossedtesticular ectopia, is an equally rare condition. It occurs when both testicles descend to the same side of the scrotum.
Transverse testicular ectopia usually occurs alongside other congenital conditions such as hypospadias (in which the opening of theurethrais not at the tip of the penis).
Congenital Hydrocele
Hydrocele occurs when a testicle descends into the scrotum along with some of the lining of the abdomen. But, rather than shriveling up and closing like it’s supposed to, the lining may have a tiny opening that allows body fluids to leak into the scrotum.
However, if the swelling is especially severe, minor surgery can be needed to drain the scrotum. Left untreated, the extreme swelling can cause damage to the testes and adjacent structures, affecting future fertility. Hydrocele that continues beyond the age of two may also need treatment.
Associated Medical Conditions
Beyond congenital disorders affecting the testes, there are also medical conditions that can affect the testes later in life.
Orchitis
Among older children and adults withmumps, orchitis occurs in up to 40% of cases, typically bilaterally (meaning both sides). Of those affected, 30% will have impaired fertility or infertility.
Varicocele
Varicoceleis another common condition affecting the testes. It involves an abnormal enlargement of veins within the scrotum (similar tovaricose veins) that can starve the testicles of the blood needed to produce healthy sperm.
In addition to scrotal discomfort and pain, varicoceles can decrease testosterone production, leading to reduced fertility. Studies suggest that up to 15% of males and more than a third of males with infertility are diagnosed with varicocele.
Testicular Torsion
Testicular torsionoccurs when the testicle rotates inside the scrotum, cutting off the blood supply. Symptoms include pain and swelling of the testicle, typically sudden and severe. Nausea, vomiting, and an abnormal elevation of the testicle are also common.
Testicular torsion can happen to males of any age but is most common in 12- to 18-year-olds. It can happen after strenuous exercise, while sleeping, or after a blow or injury to the scrotum.
When to Seek Emergency CareTesticular torsion is a medical emergency. Unless the flow of blood is restored within six hours, the risk of testicular damage and infertility is high. Severe cases can even result in the loss of the testicle.
When to Seek Emergency Care
Testicular torsion is a medical emergency. Unless the flow of blood is restored within six hours, the risk of testicular damage and infertility is high. Severe cases can even result in the loss of the testicle.
Testicular Cancer
Testicular cancer affects thousands of males each year in the United States. Fortunately, the disease is highly curable, and death rates are low. Unlike other cancers, it is more likely to affect younger males than older males.
Symptoms of testicular cancer include a painless lump on a testicle, a dull ache in the groin or abdomen, a feeling of heaviness in the scrotum, and back pain. Risk factors include having an undescended testicle and a family history of testicular cancer.
According to the National Cancer Institute, an estimated 9,750 men in the United States were diagnosed with testicular cancer in 2023 with roughly 500 deaths attributed to the disease.
Testicular cancer accounts for less than 1% of all cancers in the U.S. with arelative five-year survival rateof 95% (meaning that 95 out of 100 men will live forat leastfive years after their diagnosis).
The diagnosis of testicle problems usually involves a physical examination and imaging studies to look for abnormalities within or surrounding the testicles.
The physical exam involvespalpation(light touching) to detect lumps, swelling, or other abnormalities on or around the testes. The healthcare provider may also manipulate your leg, pelvis, or torso to check for pain or the abnormal movement of a testicle.
Ultrasoundis the most commonly used tool to examine the testes. This non-invasive test uses sound waves to look inside the scrotum for any abnormalities. It can also check if the blood flow is normal or for signs of testicular torsion, testicular cancer, and varicocele.
Magnetic resonance imaging (MRI)uses powerful magnetic and radio waves to create highly detailed images of soft tissues. An MRI is the test of choice for diagnosing cryptorchidism. It can also help differentiatebenign(noncancerous) lumps frommalignant(cancerous) ones.
Summary
The testes (testicles) are two egg-shaped organs housed within the scrotum that play a central role in male fertility and function. They are tasked with producing sperm as well as the sex hormone testosterone.
There are several congenital conditions that can affect the testes, including cryptorchidism (undescended testicle) and hydrocele. The testicles are also vulnerable to other medical conditions such as orchitis, varicocele, testicular torsion, and testicular cancer.
19 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Cancer Institute.Anatomy of the testis.Standring S.Male reproductive system. In:Gray’s Anatomy: The Anatomical Basis of Clinical Practice. Amsterdam, Netherlands: Elsevier; 2016.Hines M, Constaninescu M, Spencer D.Early androgen exposure and human gender development.Biol Sex Differ. 2015;6:3. doi:10.1186/s13293-015-0022-1Corona G, Maggi M.The role of testosterone in male sexual function.Rev Endocr Metab Disord. 2022;23(6):1159–1172. doi:10.1007/s11154-022-09748-3Nishimura H, L’Hernault SW.Spermatogenesis.Curr Biol.2017 Sep 25;27(18):R988-R994. doi:10.1016/j.cub.2017.07.067Gurney JK, Mcglynn KA, Stanley J, et al.Risk factors for cryptorchidism.Nat Rev Urol. 2017;14(9):534-548. doi:10.1038/nrurol.2017.90Piltoft JS, Larsen SB, Dalton SO, et al.Early life risk factors for testicular cancer: a case-cohort study based on the Copenhagen School Health Records Register.Acta Oncol. 2017;56(2):220-224. doi:10.1080/0284186X.2016.1266085Children’s Hospital of Philadelphia.Retractile testicles.Myers A, Morganstern B, Fine R.A unique case of pentaorchidism.Urology. 2017;104:196-197. doi:10.1016/j.urology.2017.03.017Kajal P, Rattan KN, Bhutani N, Sangwan V.Transverse testicular ectopia with scrotal hypospadias but without inguinal hernia - case report of a rare association.Int J Surg Case Rep. 2017;31:167-169. doi:10.1016/j.ijscr.2017.01.044Acer-Demir T, Ekenci BY, Ozer D, et al.Natural history and conservative treatment outcomes for hydroceles: a retrospective review of one center’s experience.Urology. 2018 Feb:112:155-160. doi:10.1016/j.urology.2017.10.003MedlinePlus.Orchitis.Wu H, Wang F, Tang D, Han D.Mumps orchitis: clinical aspects and mechanisms.Front Immunol.2021;12:582946. doi:10.3389/fimmu.2021.582946Alsaikhan B, Alrabeeah K, Delouya G, Zini A.Epidemiology of varicocele.Asian J Androl.2016;18(2):179-81. doi:10.4103/1008-682X.172640Hyun GS.Testicular torsion.Rev Urol.2018;20(2):104–106. doi:10.3909/riu0800Baird DC, Meyers GJ, Hu JC.Testicular cancer: diagnosis and treatment.Am Fam Physician.2018;97(4):261-268.National Cancer Institute.Cancer stat facts: testicular cancer.Kuhn AL, Scortegagna E, Nowitzki KM, Kim YH.Ultrasonography of the scrotum in adults.Ultrasonography. 2016 Jul;35(3):180–197. doi:10.14366/usg.15075Tsili AC, Bertolotto M, Turgut AT, et al.MRI of the scrotum: recommendations of the ESUR Scrotal and Penile Imaging Working Group.Eur Radiol. 2018;28(1):31-43. doi:10.1007/s00330-017-4944-3
19 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Cancer Institute.Anatomy of the testis.Standring S.Male reproductive system. In:Gray’s Anatomy: The Anatomical Basis of Clinical Practice. Amsterdam, Netherlands: Elsevier; 2016.Hines M, Constaninescu M, Spencer D.Early androgen exposure and human gender development.Biol Sex Differ. 2015;6:3. doi:10.1186/s13293-015-0022-1Corona G, Maggi M.The role of testosterone in male sexual function.Rev Endocr Metab Disord. 2022;23(6):1159–1172. doi:10.1007/s11154-022-09748-3Nishimura H, L’Hernault SW.Spermatogenesis.Curr Biol.2017 Sep 25;27(18):R988-R994. doi:10.1016/j.cub.2017.07.067Gurney JK, Mcglynn KA, Stanley J, et al.Risk factors for cryptorchidism.Nat Rev Urol. 2017;14(9):534-548. doi:10.1038/nrurol.2017.90Piltoft JS, Larsen SB, Dalton SO, et al.Early life risk factors for testicular cancer: a case-cohort study based on the Copenhagen School Health Records Register.Acta Oncol. 2017;56(2):220-224. doi:10.1080/0284186X.2016.1266085Children’s Hospital of Philadelphia.Retractile testicles.Myers A, Morganstern B, Fine R.A unique case of pentaorchidism.Urology. 2017;104:196-197. doi:10.1016/j.urology.2017.03.017Kajal P, Rattan KN, Bhutani N, Sangwan V.Transverse testicular ectopia with scrotal hypospadias but without inguinal hernia - case report of a rare association.Int J Surg Case Rep. 2017;31:167-169. doi:10.1016/j.ijscr.2017.01.044Acer-Demir T, Ekenci BY, Ozer D, et al.Natural history and conservative treatment outcomes for hydroceles: a retrospective review of one center’s experience.Urology. 2018 Feb:112:155-160. doi:10.1016/j.urology.2017.10.003MedlinePlus.Orchitis.Wu H, Wang F, Tang D, Han D.Mumps orchitis: clinical aspects and mechanisms.Front Immunol.2021;12:582946. doi:10.3389/fimmu.2021.582946Alsaikhan B, Alrabeeah K, Delouya G, Zini A.Epidemiology of varicocele.Asian J Androl.2016;18(2):179-81. doi:10.4103/1008-682X.172640Hyun GS.Testicular torsion.Rev Urol.2018;20(2):104–106. doi:10.3909/riu0800Baird DC, Meyers GJ, Hu JC.Testicular cancer: diagnosis and treatment.Am Fam Physician.2018;97(4):261-268.National Cancer Institute.Cancer stat facts: testicular cancer.Kuhn AL, Scortegagna E, Nowitzki KM, Kim YH.Ultrasonography of the scrotum in adults.Ultrasonography. 2016 Jul;35(3):180–197. doi:10.14366/usg.15075Tsili AC, Bertolotto M, Turgut AT, et al.MRI of the scrotum: recommendations of the ESUR Scrotal and Penile Imaging Working Group.Eur Radiol. 2018;28(1):31-43. doi:10.1007/s00330-017-4944-3
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
National Cancer Institute.Anatomy of the testis.Standring S.Male reproductive system. In:Gray’s Anatomy: The Anatomical Basis of Clinical Practice. Amsterdam, Netherlands: Elsevier; 2016.Hines M, Constaninescu M, Spencer D.Early androgen exposure and human gender development.Biol Sex Differ. 2015;6:3. doi:10.1186/s13293-015-0022-1Corona G, Maggi M.The role of testosterone in male sexual function.Rev Endocr Metab Disord. 2022;23(6):1159–1172. doi:10.1007/s11154-022-09748-3Nishimura H, L’Hernault SW.Spermatogenesis.Curr Biol.2017 Sep 25;27(18):R988-R994. doi:10.1016/j.cub.2017.07.067Gurney JK, Mcglynn KA, Stanley J, et al.Risk factors for cryptorchidism.Nat Rev Urol. 2017;14(9):534-548. doi:10.1038/nrurol.2017.90Piltoft JS, Larsen SB, Dalton SO, et al.Early life risk factors for testicular cancer: a case-cohort study based on the Copenhagen School Health Records Register.Acta Oncol. 2017;56(2):220-224. doi:10.1080/0284186X.2016.1266085Children’s Hospital of Philadelphia.Retractile testicles.Myers A, Morganstern B, Fine R.A unique case of pentaorchidism.Urology. 2017;104:196-197. doi:10.1016/j.urology.2017.03.017Kajal P, Rattan KN, Bhutani N, Sangwan V.Transverse testicular ectopia with scrotal hypospadias but without inguinal hernia - case report of a rare association.Int J Surg Case Rep. 2017;31:167-169. doi:10.1016/j.ijscr.2017.01.044Acer-Demir T, Ekenci BY, Ozer D, et al.Natural history and conservative treatment outcomes for hydroceles: a retrospective review of one center’s experience.Urology. 2018 Feb:112:155-160. doi:10.1016/j.urology.2017.10.003MedlinePlus.Orchitis.Wu H, Wang F, Tang D, Han D.Mumps orchitis: clinical aspects and mechanisms.Front Immunol.2021;12:582946. doi:10.3389/fimmu.2021.582946Alsaikhan B, Alrabeeah K, Delouya G, Zini A.Epidemiology of varicocele.Asian J Androl.2016;18(2):179-81. doi:10.4103/1008-682X.172640Hyun GS.Testicular torsion.Rev Urol.2018;20(2):104–106. doi:10.3909/riu0800Baird DC, Meyers GJ, Hu JC.Testicular cancer: diagnosis and treatment.Am Fam Physician.2018;97(4):261-268.National Cancer Institute.Cancer stat facts: testicular cancer.Kuhn AL, Scortegagna E, Nowitzki KM, Kim YH.Ultrasonography of the scrotum in adults.Ultrasonography. 2016 Jul;35(3):180–197. doi:10.14366/usg.15075Tsili AC, Bertolotto M, Turgut AT, et al.MRI of the scrotum: recommendations of the ESUR Scrotal and Penile Imaging Working Group.Eur Radiol. 2018;28(1):31-43. doi:10.1007/s00330-017-4944-3
National Cancer Institute.Anatomy of the testis.
Standring S.Male reproductive system. In:Gray’s Anatomy: The Anatomical Basis of Clinical Practice. Amsterdam, Netherlands: Elsevier; 2016.
Hines M, Constaninescu M, Spencer D.Early androgen exposure and human gender development.Biol Sex Differ. 2015;6:3. doi:10.1186/s13293-015-0022-1
Corona G, Maggi M.The role of testosterone in male sexual function.Rev Endocr Metab Disord. 2022;23(6):1159–1172. doi:10.1007/s11154-022-09748-3
Nishimura H, L’Hernault SW.Spermatogenesis.Curr Biol.2017 Sep 25;27(18):R988-R994. doi:10.1016/j.cub.2017.07.067
Gurney JK, Mcglynn KA, Stanley J, et al.Risk factors for cryptorchidism.Nat Rev Urol. 2017;14(9):534-548. doi:10.1038/nrurol.2017.90
Piltoft JS, Larsen SB, Dalton SO, et al.Early life risk factors for testicular cancer: a case-cohort study based on the Copenhagen School Health Records Register.Acta Oncol. 2017;56(2):220-224. doi:10.1080/0284186X.2016.1266085
Children’s Hospital of Philadelphia.Retractile testicles.
Myers A, Morganstern B, Fine R.A unique case of pentaorchidism.Urology. 2017;104:196-197. doi:10.1016/j.urology.2017.03.017
Kajal P, Rattan KN, Bhutani N, Sangwan V.Transverse testicular ectopia with scrotal hypospadias but without inguinal hernia - case report of a rare association.Int J Surg Case Rep. 2017;31:167-169. doi:10.1016/j.ijscr.2017.01.044
Acer-Demir T, Ekenci BY, Ozer D, et al.Natural history and conservative treatment outcomes for hydroceles: a retrospective review of one center’s experience.Urology. 2018 Feb:112:155-160. doi:10.1016/j.urology.2017.10.003
MedlinePlus.Orchitis.
Wu H, Wang F, Tang D, Han D.Mumps orchitis: clinical aspects and mechanisms.Front Immunol.2021;12:582946. doi:10.3389/fimmu.2021.582946
Alsaikhan B, Alrabeeah K, Delouya G, Zini A.Epidemiology of varicocele.Asian J Androl.2016;18(2):179-81. doi:10.4103/1008-682X.172640
Hyun GS.Testicular torsion.Rev Urol.2018;20(2):104–106. doi:10.3909/riu0800
Baird DC, Meyers GJ, Hu JC.Testicular cancer: diagnosis and treatment.Am Fam Physician.2018;97(4):261-268.
National Cancer Institute.Cancer stat facts: testicular cancer.
Kuhn AL, Scortegagna E, Nowitzki KM, Kim YH.Ultrasonography of the scrotum in adults.Ultrasonography. 2016 Jul;35(3):180–197. doi:10.14366/usg.15075
Tsili AC, Bertolotto M, Turgut AT, et al.MRI of the scrotum: recommendations of the ESUR Scrotal and Penile Imaging Working Group.Eur Radiol. 2018;28(1):31-43. doi:10.1007/s00330-017-4944-3
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