Testicular agenesis is a rare condition present from birth in which one or both testicles do not develop. Many people first hear about testicular agenesis in infancy or childhood, but some are recognized later during puberty or fertility testing. Early signs of testicular agenesis can include an empty scrotum, a smaller scrotum, delayed puberty, or trouble having children, and not everyone will have the same features. The condition is lifelong, and the outlook depends on whether one or both testicles are absent and on any related health issues, but testicular agenesis itself is not usually life-threatening. Treatment focuses on management and may include hormone replacement if needed, surgery for related concerns, a testicular prosthesis for appearance, and fertility support when appropriate.
How many people live with Testicular agenesis?
There is no single direct worldwide or U.S. count for testicular agenesis. Widely used rare-disease sources suggest that the complete form, meaning being born without both testicles, affects about 1 in 20,000 males (Orphanet, 2024). Using that rate, a rough estimate is about 200,000 people worldwide (Orphanet, 2024; UN World Population Prospects, 2024) and about 8,400 people in the United States (Orphanet, 2024; U.S. Census Bureau, 2024).
Overview
Testicular agenesisSymptoms
Testicular agenesis means one or both testicles do not develop. Signs can include an empty scrotum at birth, later delayed puberty if both are affected, and possible fertility problems or lower testosterone.
Outlook and prognosis
With testicular agenesis, long-term health depends on hormone levels and fertility needs. Many do well with testosterone replacement, which can support puberty, sexual function, bone strength, and energy; fertility is usually affected.
Causes and risk factors
Testicular agenesis usually begins before birth when a testicle does not form, most often from a new genetic change, and sometimes as part of an inherited condition. Family history can raise risk, while lifestyle or environmental factors are not known primary causes.
Genetic influences
Genetics can be important in testicular agenesis, but many cases have no single clear genetic cause. Changes in genes involved in sex development may play a role, and genetic testing can sometimes help explain why testicular agenesis happened.
Diagnosis
Testicular agenesis is usually diagnosed when one or both testicles cannot be found on exam or imaging. The diagnosis of testicular agenesis may be confirmed with ultrasound, hormone tests, and sometimes genetic tests to rule out other conditions.
Treatment and drugs
Treatment for testicular agenesis depends on whether one or both testes are absent and on age, puberty, and hormone levels. Many living with testicular agenesis may need testosterone treatment, along with fertility counseling, regular hormone checks, and the option of a testicular implant.
Symptoms
Testicular agenesis can come to attention in different ways. Some people with Testicular agenesis are noticed in infancy because one or both testes cannot be felt in the scrotum, while others first learn about it during puberty or a fertility evaluation. The changes are often subtle at first, blending into daily life until they become more noticeable. The early features of Testicular agenesis depend a lot on whether one testis or both are absent.
One or both sides of the scrotum may look or feel empty because a testis is not present. This is often first noticed during a newborn exam, a diaper change, or later at a routine checkup.
If both testes are absent, puberty may start late, be incomplete, or not begin without treatment. Many living with Testicular agenesis may have less voice deepening, less facial and body hair, and less muscle growth than expected.
Low testosterone can cause low energy, lower sex drive, and fewer spontaneous erections in the teen years or adulthood. Over time, it can also affect bone strength and how the body builds muscle and stores fat.
Bilateral Testicular agenesis causes infertility because sperm are not made without testicular tissue. If only one testis is absent, fertility may be normal or only slightly affected.
How people usually first notice Testicular agenesis?
Testicular agenesis is usually first noticed when a baby is born with one or both testicles not felt in the scrotum during a newborn exam, or when prenatal ultrasound raises questions about typical male genital development. As childhood goes on, how testicular agenesis is first noticed may also include a testicle that never seems to descend, a smaller scrotum on one or both sides, or later concern at puberty if typical testicular growth does not happen. Because an undescended testicle can look similar at first, doctors usually confirm the first signs of testicular agenesis with a physical exam and imaging, and sometimes with hormone or genetic testing.
Types of Testicular agenesis
Testicular agenesis can affect day-to-day life in different ways depending on whether one testicle is missing or both are absent from birth. In practice, the main types of testicular agenesis are based on this difference, because it strongly affects puberty, fertility, and hormone production. Symptoms don’t always look the same for everyone. Some people are diagnosed in infancy because a testicle cannot be found, while others are only recognized later during puberty or a fertility workup.
Unilateral agenesis
This means one testicle is absent from birth while the other is present, and it is one of the recognized types of testicular agenesis. Many living with this form go through puberty normally and may have few or no obvious symptoms if the remaining testicle works well. It is often found when an undescended or nonpalpable testicle is being checked.
Bilateral agenesis
This means both testicles are absent from birth, sometimes called congenital anorchia in medical terms. Because the body makes little or no testicular testosterone, early symptoms of testicular agenesis in this form may include a small penis in infancy and delayed or absent puberty later on. Fertility is not possible without testicular tissue, and hormone treatment is usually needed.
Can I slow down the onset of symptoms?
No. Testicular agenesis means one or both testicles did not form before birth, so there is no proven lifestyle change, diet, exercise, or supplement that can delay the condition or prevent it from being there; this is different from lowering risk, because the condition is already present from birth. What can help is early care with a hormone specialist, since checking hormone levels and starting treatment such as testosterone replacement when needed may reduce later problems like delayed puberty, low energy, and weak bones, and while this cannot change the underlying condition, early support can still improve day-to-day health.
What genetics can tell you about symptoms
Genetics can sometimes help explain why testicular agenesis happens and, in some cases, why signs differ from one person to another, especially if it occurs as part of a broader difference in sex development. Certain genetic changes may affect whether both testes are absent or only one, how the genitals developed before birth, and how strongly hormone-related features such as delayed puberty or infertility show up later, but not everyone with testicular agenesis has an identifiable genetic cause. In short, genetic testing may offer clues about which features are likely, how severe they may be, and whether other body systems could also be affected, although symptoms can still vary widely even among people with the same genetic finding.
Causes and risk factors
Testicular agenesis usually starts very early in pregnancy, and the exact cause is not always found. An inherited or new genetic change that affects early testis development is a recognized cause. Family history and problems with early hormone signals are among the risk factors for testicular agenesis. Some medicines, smoking, alcohol, and chemical exposures during pregnancy have been studied as factors that may modify risk, but they are not known to be the main cause. Researchers are still learning how these pieces fit together.
What are the most common causes or risk factors?
Testicular agenesis usually begins before birth, when one or both testicles do not form as expected in the womb. In many people, the exact cause is never found, but it may sometimes be linked to a problem very early in the baby's growth, such as loss of blood flow to the developing testicle; more rarely, it is related to differences in genes or chromosomes that affect how the reproductive organs develop. There are no clear lifestyle risk factors, and it is usually not caused by anything a parent did during pregnancy.
Environmental and biological risk factors
Testicular agenesis is present before birth, and many cases have no single clear explanation. The best-known risk factors for testicular agenesis involve events very early in fetal development, when the testes are first forming. Doctors often group risks into internal (biological) and external (environmental).
The testes begin forming very early in pregnancy, often before many people know they are pregnant. If development is disrupted at that stage, testicular agenesis can occur.
Normal testicular formation depends on well-timed hormone signals in the developing fetus. Problems with these signals can increase the chance that testicular tissue does not form as expected.
Certain maternal health conditions, especially diabetes or severe illness early in pregnancy, are linked with a higher risk of birth differences affecting genital development. They may contribute to testicular agenesis, although most pregnancies with these conditions do not lead to it.
People with other differences in the reproductive tract may be more likely to have testicular agenesis because these structures develop together in the womb. This points to a shared biological disruption early in fetal growth.
Genetic risk factors
For families trying to understand why one or both testes did not develop, the genetic causes of testicular agenesis can sometimes be traced to chromosome differences or gene changes that act very early in fetal development. In some children, especially when both testes are absent or there are other genital differences, doctors are more likely to find an underlying genetic explanation. Carrying a genetic change doesn’t guarantee the condition will appear, and many living with testicular agenesis never get one single clear genetic answer.
Family history: A family history of infertility, undescended testes, genital differences, or testicular agenesis can point to an inherited risk. This pattern does not prove the same condition will recur, but it can make genetic counseling more useful.
Sex chromosomes: Changes involving the sex chromosomes, especially the Y chromosome, can interrupt the early steps that start testis formation. Sometimes the change affects a single gene, and sometimes it affects a larger piece of DNA.
SRY pathway: Changes in the gene called SRY, or in genes that work closely with it, can stop the usual signal that turns early tissue into a testis. When that signal is disrupted very early, testicular agenesis can result.
Other key genes: Other genes that help the early gonad grow and mature into a testis, such as NR5A1, WT1, and SOX9, can also be involved. Depending on the gene, there may also be other findings, including genital differences or kidney problems.
DNA segment changes: Missing or extra stretches of DNA can disrupt genes needed for normal testis formation. These changes are uncommon but are a recognized genetic cause in some families and some isolated cases.
New gene changes: Some gene changes happen for the first time in the child and are not found in either parent. This helps explain why testicular agenesis can appear even when there is no family history.
Lifestyle risk factors
Testicular agenesis is present from birth, so lifestyle habits do not cause it. However, how lifestyle affects testicular agenesis can matter for hormone balance, fertility planning, bone and muscle health, and long-term cardiovascular risk, especially if testosterone levels are low or replacement therapy is needed. The most important factors are those that influence metabolic health, reproductive function, and treatment safety.
Excess body fat can lower available testosterone and increase conversion of testosterone to estrogen. In someone with testicular agenesis, this can worsen low-energy, low-libido, and body-composition symptoms if hormone production is already limited.
Regular resistance and aerobic exercise helps support muscle mass, bone strength, and metabolic health. For people with testicular agenesis, this may reduce some effects of testosterone deficiency and improve overall response to treatment plans.
Heavy alcohol intake can impair sexual function, reduce fertility potential, and worsen liver-related problems that affect hormone metabolism. This is especially relevant when only one testis is present or when testosterone replacement is being monitored.
Smoking is linked to poorer blood vessel health and reduced sperm quality. In testicular agenesis, that can further affect sexual health and fertility potential when reproductive capacity is already lower or uncertain.
Risk prevention
Testicular agenesis is usually a congenital condition, which means the testicle does not form before birth, so there is no proven way to prevent the condition itself. For many living with testicular agenesis, prevention is mainly about lowering the risk of complications such as low testosterone, delayed or incomplete puberty, fertility problems, and emotional stress. Some prevention is universal, others are tailored to people with specific risks. Early follow-up also helps doctors watch for concerns that can overlap with the early symptoms of testicular agenesis, especially in childhood and puberty.
Regular visits with a pediatrician, family doctor, or hormone specialist can help catch growth, puberty, or hormone problems early. In people with testicular agenesis, this can lower the risk of delayed treatment and long-term complications.
Blood tests may be used to check testosterone and other hormones at key stages such as infancy, childhood, and puberty. If levels are low, timely treatment can support bone strength, energy, sexual development, and general well-being.
Watching closely for normal puberty changes can help families and doctors act early if development is delayed or incomplete. Many with testicular agenesis benefit from prompt assessment if the voice does not deepen, muscle mass stays low, or body hair develops slowly.
If both testes are absent, fertility is usually affected, so early counseling can help people understand options and plan ahead. In unilateral testicular agenesis, checking the remaining testicle and discussing future fertility may still be useful.
Can you prevent Testicular agenesis?
No, there is no known way to prevent testicular agenesis, which means a baby is born without one or both testicles. It usually happens very early before birth, and in most cases the exact cause is not clear, so it is not something parents can usually control. Good prenatal care is still important for overall pregnancy health, but it has not been proven to prevent this condition.
Transmission
Testicular agenesis is not infectious at all, so it cannot be caught from another person through contact, sex, blood, or the air. Instead, testicular agenesis is a congenital condition, meaning it develops before birth when one or both testicles do not form.
The genetic transmission of testicular agenesis is often unclear: many cases happen sporadically, while some are linked to a genetic change that is new in the child or, less often, part of a broader condition that can run in families. If there is a family history or other differences in development, a genetics specialist can explain the chance of it happening again in a future pregnancy.
When to test your genes
Genetic testing is worth discussing when a baby is born with one or both testes absent, when there are other differences in genital development, or later if delayed puberty or infertility raises questions. It can help confirm the cause, look for related hormone or chromosome conditions, and guide care and family counseling.
Diagnosis
Testicular agenesis is usually suspected when one or both testicles cannot be felt during a newborn exam, childhood checkup, or later fertility evaluation. Doctors usually confirm the diagnosis by combining the physical exam with hormone tests, imaging, and sometimes genetic testing. The diagnosis of testicular agenesis can take time because an absent testicle can look similar to an undescended testicle, especially early on.
A doctor checks whether one or both testicles can be felt in the scrotum or groin. They also look at the penis, scrotum, and overall pubertal development to see whether there are signs of a related difference in sex development.
A detailed family and health history can help uncover clues from pregnancy, birth, puberty, and fertility. Doctors also ask about prior surgery, injury, or infection, because these can affect how the findings are interpreted.
Blood tests can measure hormones linked to testicular tissue, such as testosterone, luteinizing hormone, follicle-stimulating hormone, and anti-Mullerian hormone. These results can help show whether working testicular tissue is present somewhere in the body.
Ultrasound may be used to look for a testicle in the scrotum or groin without surgery. It can be helpful, but a normal or unclear scan does not always rule in or rule out testicular agenesis.
How is Testicular agenesis diagnosed?
Testicular agenesis is usually suspected when one or both testicles cannot be felt in the scrotum during an exam, often in a baby or child, and the doctor will also ask about growth and development. Blood tests can help show whether any working testicular tissue is present, and scans such as ultrasound may be used, although they do not always give a clear answer. In some cases, a small operation using a tiny camera is needed to confirm that a testicle never formed, and genetic testing may be offered, especially if both are absent or there are other concerns about development before birth.
Stages of Testicular agenesis
Testicular agenesis does not have defined progression stages. This is because it is a difference present from before birth, rather than an illness that gradually moves from mild to severe over time. Many people feel reassured knowing what their tests can—and can’t—show. Doctors usually work out how testicular agenesis is diagnosed using a physical exam, hormone blood tests, imaging such as ultrasound, and sometimes genetic testing to confirm the cause and check for related differences in sexual development.
Outlook and prognosis
The outlook for testicular agenesis is generally good when only one testis is absent, because the remaining testis often produces enough testosterone and sperm for normal puberty, sexual function, and potential fertility. Bilateral absence has a much greater lifelong impact, with infertility expected and testosterone replacement usually needed to support puberty, bone health, muscle mass, and sexual development. Life expectancy is typically normal, and testicular agenesis itself is not usually associated with increased mortality. Prognosis also depends on whether it occurs alone or as part of a broader disorder of sex development or congenital syndrome, in which case associated medical issues can influence long-term outcomes. Ongoing follow-up with endocrinology, urology, and fertility specialists can help optimize hormone health, reproductive counseling, and psychosocial well-being.
Long-term effects
For many people, the long-term effects of testicular agenesis depend on whether one testicle is absent or both are absent. Long-term effects vary widely, because one healthy testicle can often make enough testosterone and sperm for normal puberty, sexual development, and fertility. When both testicles are absent, the long-term picture is usually more significant and can affect puberty, fertility, bone health, and body composition. Some people also have other reproductive or genital differences that shape their outlook over time.
Fertility may be normal with testicular agenesis affecting one side if the remaining testicle works well. If both testicles are absent, natural sperm production does not occur and biological fertility is not possible.
When both testicles are absent, puberty often does not begin on its own or remains incomplete. This can mean less deepening of the voice, less facial and body hair, and slower growth of the penis and scrotum.
Long-term low testosterone can lead to low energy, reduced sex drive, and less muscle mass over time. Some may also find that erections are less reliable if hormone levels stay very low.
Testosterone helps build and maintain strong bones through adolescence and adulthood. Without enough of it over many years, bones can become thinner and break more easily.
How is it to live with Testicular agenesis?
Living with testicular agenesis can affect daily life in quiet but important ways, especially around puberty, fertility, body image, sexual health, and decisions about hormone treatment. Many people with this condition need ongoing care to check testosterone levels, support bone and muscle health, and talk through options such as hormone replacement or testicular prostheses, while some may also face infertility and the emotional weight that can come with it. For partners, parents, and other loved ones, the condition can bring questions, worry, and conversations about identity, future family-building, and medical care, but with clear information and steady support, many people with testicular agenesis live full, healthy lives.
Treatment and drugs
Testicular agenesis is treated by focusing on the effects of having no working testicular tissue, rather than reversing the condition itself. In children and teens, treatment often centers on testosterone replacement to support puberty, sexual development, muscle and bone strength, and energy, while adults may need ongoing hormone therapy to keep these effects stable over time. Some people with testicular agenesis may also be offered surgery for an artificial testicle if they want a more typical scrotal appearance, and counseling can help with body image, relationships, and questions about fertility. Not every treatment works the same way for every person, so care is usually tailored to age, symptoms, hormone levels, and whether there are other differences in genital development. Regular follow-up is important to adjust treatment and watch for long-term issues such as low bone density, especially when managing testicular agenesis from childhood onward.
Can you cure Testicular agenesis?
No, testicular agenesis cannot be cured, because the testicles did not form before birth and cannot be made to grow later. Treatment can still help a lot by replacing missing testosterone to support puberty, sexual health, energy, and bone strength, and some people also choose an implant to create a more typical look.
Non-drug treatment
Living with testicular agenesis can affect puberty, fertility, body image, and sexual health, so care often goes beyond medicines alone. Managing this condition often means working with specialists to support emotional well-being, plan for fertility questions, and address physical concerns such as an empty scrotum. The best non-drug care depends on whether one or both testes are absent and on a person’s age and goals. Many people looking into treatment options for testicular agenesis use a mix of counseling, specialist follow-up, and sometimes surgery.
Talking with a mental health professional can help with anxiety, low mood, or body image concerns linked to testicular agenesis. This can be especially helpful during puberty, dating, or when thinking about future fertility.
A prosthetic testicle can be placed surgically to make the scrotum look and feel more typical. This does not improve hormone levels or fertility, but many people find it helps comfort and confidence.
Fertility specialists can explain how testicular agenesis may affect the ability to have biological children. You may need to try more than one strategy, and options can include semen testing when relevant, assisted reproduction, or family-building alternatives.
Genetic counseling can help families understand whether testicular agenesis happened by chance or as part of a broader genetic condition. It may also guide decisions about testing, future pregnancies, and screening for related differences in development.
Your genes may have an impact on how drugs work for you
For people living with testicular agenesis, the main medicine used is usually testosterone replacement to support puberty, sexual development, energy, bone strength, and overall well-being. At this time, there are no well-established gene-based tests that doctors routinely use to predict how well testosterone will work or what side effects someone may have in this condition; in day-to-day care, treatment is usually adjusted based on symptoms, blood test results, age, and overall health. In other words, while genes can affect how the body handles some medicines, that is not a major part of standard treatment planning for testicular agenesis right now.
Pharmacological treatments
With testicular agenesis, medicines do not replace a missing testicle, but some people need hormone treatment if the body is not making enough testosterone. This matters most in bilateral testicular agenesis, where both testes are absent, because low testosterone can affect puberty, sexual development, energy, bone strength, and mood. Not everyone responds to the same medication in the same way. If one testicle is absent and the other works normally, medication often is not needed.
Testosterone injections, such as testosterone cypionate or testosterone enanthate, are commonly used when testicular agenesis causes low testosterone. They can help start or maintain puberty and support sex drive, muscle mass, and bone health.
Testosterone gel, including products such as testosterone gel 1% or 1.62%, is another option for ongoing hormone replacement. It gives steadier daily levels for many people, but care is needed to avoid skin-to-skin transfer to others.
Testosterone patches can also replace testosterone in some people living with testicular agenesis. They are changed regularly and may be useful for maintenance treatment, though skin irritation can be a problem for some.
In boys with bilateral testicular agenesis, doctors may start with low-dose testosterone and raise the dose slowly over time to mimic normal puberty. Dosing may be increased or lowered gradually to balance growth, body changes, and side effects.
Genetic influences
Questions about puberty, fertility, and whether future children could be affected are common for people with testicular agenesis. It’s natural to ask whether family history plays a role. In many cases, doctors do not find a single inherited cause, and testicular agenesis can happen without any known family history. Rarely, changes in genes that help the testes form before birth may be involved, especially when both testes are absent or there are other differences in genital development. Because the causes of testicular agenesis can be complex, genetic testing for testicular agenesis may be considered along with hormone tests and imaging, although it does not always give a clear answer. A genetics specialist can help explain what any result may mean for fertility, related health concerns, and the chance of this happening again in a family.
Is Testicular agenesis genetic?
Genetics can be important in testicular agenesis, but many cases have no single clear genetic cause. Changes in genes involved in sex development may play a role, and genetic testing can sometimes help explain why testicular agenesis happened.
Having a genetic risk is not necessarily a diagnosis
Changes in genes, often called genetic variants, are a normal part of human biology and are common across the general population. Most of these variants do not directly affect health and are simply part of natural human variation. For many genes, having a variant tied to a condition points to a possible link rather than a definite diagnosis, especially when several genes and environmental factors are involved. In some situations, though, a single well-characterized variant in a specific gene can be enough to confirm a diagnosis.
Pharmacogenetics—how genetics influence drug effects
For many living with testicular agenesis, treatment is often less about finding a special drug and more about whether the body is making enough testosterone. If one healthy testicle is present, medicine may not be needed, but if both are absent or not working, doctors may use testosterone replacement to support puberty, sexual health, bone strength, mood, and energy. Genetic changes can sometimes help explain why testicular agenesis happened, especially when it runs in a family or appears along with other hormone or genital differences.
Genetics is only one factor, and doctors usually choose the type and dose of treatment for testicular agenesis based mostly on age, treatment goals, blood test results, and side effects. In practice, routine pharmacogenetic testing is not a standard part of care, because there is not yet a well-established gene test that can reliably tell doctors which testosterone product will work best. When genetic testing for testicular agenesis is offered, it is usually to clarify the diagnosis, check for related health concerns, and help guide discussions about fertility and long-term care.
Interactions with other conditions
For many, testicular agenesis comes up alongside other differences that affect sex development, hormones, or fertility rather than causing unrelated illnesses on its own. If both testes are absent, the body may make very little testosterone, which can affect puberty, bone strength over time, sex drive, and energy, and it can also raise the chance of low bone density if hormone treatment is not in place. Some people with testicular agenesis also have changes in the kidneys or urinary tract, so doctors may check these areas too, especially if there are symptoms such as repeated urinary infections or unusual findings on scans. Doctors call it a “comorbidity” when two conditions occur together, and in this setting it may include infertility, delayed puberty, or a hormone imbalance rather than a separate disease caused by testicular agenesis itself. In some cases, testicular agenesis is part of a broader genetic or developmental condition, which is why family history, hormone tests, and imaging can matter. If you are being assessed for early symptoms of testicular agenesis or long-term effects, it helps to ask whether bone health, fertility, and urinary tract issues should also be checked.
How genes can cause diseases
Humans have more than 20,000 genes, each carrying out one or a few specific functions in the body. One gene instructs the body to digest lactose from milk, another tells the body how to build strong bones and another prevents the body's cells from beginning to multiply uncontrollably and developing into cancer. As all of these genes combined are the building instructions for our body, a defect in one of these genes can have severe health consequences.
Through decades of genetic research, we know the genetic code of any healthy/functional human gene. We have also identified that in certain positions on a gene, some individuals may have a different genetic letter from the one you have. We call these hotspots "Genetic Variations" or "Variants" in short. In many cases, studies have been able to show that having the genetic letter "G" in the position makes you healthy, but having the letter "A" in the same position disrupts the gene function and causes a disease. Genopedia allows you to view these variants in genes and summarizes all that we know from scientific research, which genetic letters (Genotype) have good or bad consequences on your health or on your traits.
What other conditions can cause similar symptoms to Testicular agenesis?
The main conditions that can look like testicular agenesis are an undescended testicle, where the testicle is present but has not moved down into the scrotum, and a "vanishing" testicle, where it formed early on but was lost before birth after its blood supply was cut off. Doctors may also think about conditions that affect sex development or hormone production, because these can also cause missing or very small testicles, delayed puberty, or trouble with fertility.
History
For families, the history of testicular agenesis is closely tied to a very practical question: when a baby or child is examined, why is one testicle or both testicles not found in the scrotum? In older medical writing, doctors could describe what they felt on examination, but they had limited ways to tell the difference between a testicle that had not moved down normally and one that had never developed. That meant many living with testicular agenesis were likely grouped together with other conditions that can look similar at first.
As medical science evolved, the picture became clearer. Better physical exams, hormone testing, imaging, and later keyhole surgery helped doctors sort out these different causes of a non-palpable testicle. This mattered in day-to-day care: a child who seemed to have an undescended testicle on a routine visit might later be found to have testicular agenesis instead, changing what follow-up and treatment made sense.
Over time, descriptions became more precise, and doctors began separating unilateral cases, where one testicle is absent, from bilateral cases, where both are absent. Early reports also used overlapping terms, including congenital absence of the testis or anorchia in some situations, although those labels were not always used consistently. Not every early description was complete, yet together they built the foundation of today’s knowledge.
In recent decades, awareness has grown that testicular agenesis is rare and that diagnosis often depends on careful evaluation rather than a single test. Researchers later identified that some cases have a genetic basis, but the main historical shift was simpler: moving from guesswork based on appearance alone to a more reliable diagnosis based on examination, hormone patterns, and direct visualization when needed. Knowing this history helps explain why early symptoms of testicular agenesis can be mistaken for other conditions at first, and why modern care usually focuses on confirming the diagnosis carefully before making decisions about surgery, hormone treatment, or long-term follow-up.