Klinefelter Syndrome Causes, Symptoms, Diagnosis, Treatment, Prevention

Klinefelter Syndrome Causes, Symptoms, Diagnosis, Treatment, Prevention

What is Klinefelter Syndrome?

In 1942, Dr. Harry Klinefelter and his coworkers at the Massachusetts General Hospital in Boston published a report about nine men who had enlarged breasts, sparse facial and body hair, small testes, and an inability to produce sperm.

By the late 1950s, researchers discovered that men with Klinefelter syndrome, as this group of symptoms came to be called, had an extra sex chromosome, XXY instead of the usual male arrangement, XY. (For a more complete explanation of the role this extra chromosome plays, see the accompanying section, "Chromosomes and Klinefelter syndrome.")

In the early 1970s, researchers around the world sought to identify males having the extra chromosome by screening large numbers of newborn babies. One of the largest of these studies, sponsored by the National Institute of Child Health and Human Development (NICHD), checked the chromosomes of more than 40,000 infants.

Based on these studies, the XXY chromosome arrangement appears to be one of the most common genetic abnormalities known, occurring as frequently as 1 in 500 to 1 in 1,000 male births. Although the syndrome's cause, an extra sex chromosome, is widespread, the syndrome itself-the set of symptoms and characteristics that may result from having the extra chromosome-is uncommon. Many men live out their lives without ever even suspecting that they have an additional chromosome.

For this reason, the term "Klinefelter syndrome" has fallen out of favor with medical researchers. Most prefer to describe men and boys having the extra chromosome as "XXY males."

In addition to occasional breast enlargement, lack of facial and body hair, and a rounded body type, XXY males are more likely than other males to be overweight, and tend to be taller than their fathers and brothers.

For the most part, these symptoms are treatable. Surgery, when necessary, can reduce breast size. Regular injections of the male hormone testosterone, beginning at puberty, can promote strength and facial hair growth-as well as bring about a more muscular body type.

A far more serious symptom, however, is one that is not always readily apparent. Although they are not mentally retarded, most XXY males have some degree of language impairment. As children, they often learn to speak much later than do other children and may have difficulty learning to read and write. And while they eventually do learn to speak and converse normally, the majority tend to have some degree of difficulty with language throughout their lives. If untreated, this language impairment can lead to school failure and its attendant loss of self esteem.

Fortunately, however, this language disability usually can be compensated for. Chances for success are greatest if begun in early childhood. Sections that follow describe possible strategies for meeting the special educational needs of many XXY males.

Klinefelter Syndrome Causes

Chromosomes and Klinefelter Syndrome

Chromosomes, the spaghetti-like strands of hereditary material found in each cell of the body, determine such characteristics as the color of our eyes and hair, our height, and whether we are male or female.

Women usually inherit two X chromosomes-one from each parent. Men tend to inherit an X chromosome from their mothers, and a Y chromosome from their fathers. Most males with the syndrome Dr. Klinefelter described, however, have an additional X chromosomes total of two X chromosomes and one Y chromosome.

Causes of Klinefelter Syndrome

Most people have 46 chromosomes. Chromosomes contain all of your genes and DNA, the building blocks of the body. Two sex chromosomes determine if you become a boy or a girl. Girls normally have two XX chromosomes. Boys normally have an X and a Y chromosome.

No one knows what puts a couple at risk for conceiving an XXY child. Advanced maternal age increases the risk for the XXY chromosome count, but only slightly. Furthermore, recent studies conducted by NICHD grantee Terry Hassold, a geneticist at Case Western Reserve University in Cleveland, OH, show that half the time, the extra chromosome comes from the father.

Dr. Hassold explained that cells destined to become sperm or eggs undergo a process known as meiosis. In this process, the 46 chromosomes in the cell separate, ultimately producing two new cells having 23 chromosomes each. Before meiosis is completed, however, chromosomes pair with their corresponding chromosomes and exchange bits of genetic material. In women, X chromosomes pair; in men, the X and Y chromosome pair. After the exchange, the chromosomes separate, and meiosis continues.

In some cases, the Xs or the X chromosome and Y chromosome fail to pair and fail to exchange genetic material. Occasionally, this results in their moving independently to the same cell, producing either an egg with two Xs, or a sperm having both an X and a Y chromosome. When a sperm having both an X and a Y chromosome fertilizes an egg having a single X chromosome, or a normal Y- bearing sperm fertilizes an egg having two X chromosomes, an XXY male is conceived.

Symptoms of Klinefelter Syndrome

  • Abnormal body proportions (long legs, short trunk, shoulder equal to hip size)
  • Abnormally large breasts (gynecomastia)
  • Infertility
  • Sexual problems
  • Less than normal amount of pubic, armpit, and facial hair
  • Small, firm testicles
  • Tall height

Diagnosis of Klinefelter Syndrome

Because they often don't appear any different from anyone else, many XXY males probably never learn of their extra chromosome. However, if they are to be diagnosed, chances are greatest at one of the following times in life: before or shortly after birth, early childhood, adolescence, and in adulthood (as a result of testing for infertility).

In recent years, many XXY males have been diagnosed before birth, through amniocentesis or chorionic villus sampling (CVS). In amniocentesis, a sample of the fluid surrounding the fetus is withdrawn. Fetal cells in the fluid are then examined for chromosomal abnormalities. CVS is similar to amniocentesis, except that the procedure is done in the first trimester, and the fetal cells needed for examination are taken from the placenta. Neither procedure is used routinely, except when there is a family history of genetic defects, the pregnant woman is older than 35, or when other medical indications are present.

"If I were going to say something to parents who have had a prenatal diagnosis, it would be 'You are so lucky that you know," said Melissa, the mother of one XXY boy. "Because there are parents who don't know that their sons have this problem. And they will never be able to help them lead a normal life. But you can."

The next most likely opportunity for diagnosis is when the child begins school. A physician may suspect a boy is an XXY male if he is delayed in learning to talk and has difficulty with reading and writing. XXY boys may also be tall and thin and somewhat passive and shy. Again, however, there are no guarantees. Some of the boys who fit this description will have the XXY chromosome count, but many others will not.

A few XXY males are diagnosed at adolescence, when excessive breast development forces them to seek medical attention. Like some chromosomally normal males, many XXY males undergo slight breast enlargement at puberty. Of these, only about a third-10 percent of XXY males in all-will develop breasts large enough to embarrass them.

The final chance for diagnosis is at adulthood, as a result of testing for infertility. At this time, an examining physician may note the undersized testes characteristic of an XXY male. In addition to infertility tests, the physician may order tests to detect increased levels of hormones known as gonadotropins, common in XXY males.

A karyotype is used to confirm the diagnosis. In this procedure, a small blood sample is drawn. White blood cells are then separated from the sample, mixed with tissue culture medium, incubated, and checked for chromosomal abnormalities, such as an extra X chromosome.

Treatment for Klinefelter Syndrome

Testosterone therapy may be prescribed. This can help:
  • Grow body hair
  • Improve appearance of muscles
  • Improve concentration
  • Improve mood and self esteem
  • Increase energy and sex drive
  • Increase strength
Most men with this syndrome are not able to get a woman pregnant. However, an infertility specialist may be able to help. A special doctor called an endocrinologist may also be helpful.

Possible Complications

Enlarged teeth with a thinning surface is very common in Klinefelter syndrome. This is called taurodontism. This can be seen on dental x-rays.
Klinefelter syndrome also increases your risk of:
  • Attention deficient hyperactivity disorder
  • Autoimmune disorders such as lupus, rheumatoid arthritis, and Sjogren syndrome
  • Breast cancer in men
  • Depression
  • Learning disabilities, including dyslexia, which affects reading
  • A rare type of tumor called an extragonadal germ cell tumor
  • Lung disease
  • Osteoporosis
  • Varicose veins

What to Tell Families, Friends, and XXY Boys

Expectant parents awaiting the arrival of their XXY baby have difficult choices to make: whom to tell-and how much to tell about their son's extra chromosome. Fortunately, however, there are some guidelines that new parents can take into account when making their decisions.

One school of thought holds that the best course is to go on slowly, waiting at least 1 year before telling anyone-grandparents included-about the child's extra chromosome. Many people are frightened by the diagnosis, and their fears will color their perceptions of the child. For example, some people may confuse the term Klinefelter's syndrome with Down syndrome, a condition resulting in mild to moderate mental retardation.

Others may prefer to reveal the diagnosis early. Some parents have found that grandparents, aunts, uncles-and even extended family members-are more supportive when given accurate information. Another important decision parents must make is when to tell their son about his diagnosis. Some experts recommend telling the child early. When the truth is withheld, children often suspect that their parents are hiding something and may imagine a condition that is worse than their actual diagnosis.

This school of thought maintains that by the time he is 10 or 11 years old, the child can be told that his cells differ slightly from those of other people. Soon after, he can be filled in on the details: that the cell difference is due to an additional X chromosome, which is responsible for his undersized testes and any reading difficulties he may have. At this time, the child can be reassured that he does not have a disease and will not become sick. The child should also be told that some people may misunderstand this information and that he should exercise discretion in sharing it with others.

By roughly the age of 12, depending on the child's emotional maturity, he can be told that he will most probably be infertile. Parents should stress that neither the X chromosome nor the infertility associated with it mean that he is in any way less masculine than other males his age. The child's parents or his physician can explain that although he may not be able to make a baby, he can consider adopting one. Parents may also need to reassure an XXY boy that his small testes will in no way interfere with his ability to have a normal sex life.

Adherents of this school of thought believe that learning about possible infertility in such a gradual manner will be less of a shock than finding out about it all at once, late in the teen years.

Conversely, other experts believe that holding back the information does not appear to do any harm. Instead, telling an XXY boy about his extra chromosome too early may have some unpleasant consequences. An 11 or 12-year-old, for example, may associate infertility with sexual disorders and other concepts he may not yet understand.

Moreover, children, when making friends, tend to share secrets. But childhood friendships may be fleeting, and early confidences are sometimes betrayed. A malicious or thoughtless child may tell all the neighborhood children that his former companion is a "freak" because he has an extra chromosome.

For this reason, the best time to reveal the information may be mid-to-late adolescence, when an XXY male is old enough to understand his condition and better able to decide with whom he wishes to share this knowledge.


According to Dr. Robinson, the director of the NICHD-funded study, XXY babies differ little from other children their age. They tend to start life as what many parents call "good" babies-quiet, undemanding, and perhaps even a little passive. As toddlers, they may be somewhat shy and reserved. They usually learn to walk later than most other children, and may have similar delays in learning to speak.

In some, the language delays may be more severe, with the child not fully learning to talk until about age 5. Others may learn to speak at a normal rate, and not meet with any problems until they begin school, where they may experience reading difficulties. A few may not have any problems at all-in learning to speak or in learning to read.

XXY males usually have difficulty with expressive language the ability to put thoughts, ideas, and emotions into words. In contrast, their faculty for receptive language-understanding what is said-is close to normal.

"It's one of the conflicts they have," said Melissa, the mother of an XXY boy. "My son can understand the conversations of other 10 year olds. But his inability to use the language the way other 10-year olds use it makes him stand out."

In addition to academic help, boys with Klinefelter's syndrome, like other language disabled children, may need help with social skills. Language is essential not only for learning the school curriculum, but also for building social relationships. By talking and listening, children make friends-in the process, sharing information, attitudes, and beliefs. Through language, they also learn how to behave-not just in the schoolroom, but also on the playground. If their sons' language disability seems to prevent them from fitting in socially, the parents of XXY boys may want to ask school officials about a social skills training program.

Throughout childhood-perhaps, even, for the rest of their lives-XXY boys retain the same temperament and disposition they first displayed as infants and toddlers. As a group, they tend to be shy, somewhat passive, and unlikely to take a leadership role. Although they do make friends with other children, they tend to have only a few friends at a time. Researchers also describe them as cooperative and eager to please.

Detecting Language Problems Early

The parents of XXY babies can compensate for their children's language disability by providing special help in language development, beginning at an early age. However, there is no easy formula to meet the language needs of all XXY boys. Like everyone else, XXY males are unique individuals. A few may not have any trouble learning to read and write, while the rest may have language impairments ranging from mild to severe.

If their son's speech seems to be lagging behind that of other children, parents should ask their child's pediatrician for a referral to a speech pathologist for further testing. A speech pathologist specializes in the disorders of voice, speech, and language. (The American Speech, Language and Hearing Association, listed in the reference section, distributes a free pamphlet on the stages of language development during the first 5 years of life.)

Parents should also pay particular attention to their children's hearing. Like other small children, XXY infants and toddlers may suffer from frequent ear infections. With any child, such infections may impair hearing and delay the acquisition of language. Such a hearing impairment may be a further setback for an XXY child who is already having language difficulties.

Guidelines for Detecting Language Problems

Shortly after the first birthday, children should be able to make their wishes known with simple one word utterances. For example, a child may say "milk" to mean "I want more milk." Gradually, children begin to combine words to produce two-word sentences, such as "More milk." By age three, most children use an average of about four words per sentence.

If a child is not communicating effectively with single words by 18 to 24 months, then parents should seek a consultation with a speech and language pathologist.

The XXY Boy in the Classroom

Although there are exceptions, XXY boys are usually well behaved in the classroom. Most are shy, quiet, and eager to please the teacher. But when faced with material they find difficult, they tend to withdraw into quiet daydreaming. Teachers sometimes fail to realize they have a language problem, and dismiss them as lazy, saying they could do the work if they would only try. Many become so quiet that teachers forget they're even in the room. As a result, they fall farther and farther behind, and eventually may be held back a grade.

Teaching Tips

XXY males often have decreased immediate auditory recall they have trouble remembering what they have just heard. Parents and teachers can help them remember by approaching memory through visual channels. Illustrating words with pictures may help. Gesturing is another useful technique. For example, a teacher might accompany the word "yes" with a nod of the head. Similarly, shaking the head from side to side is the universal gesture for "no." Other useful gestures include waving goodbye, showing the child an upraised palm to indicate "stop," and holding the arms outstretched to mean "so big."

XXY males frequently have trouble finding the right word to describe an object or a situation. Parents and teachers can help them build vocabulary through a variety of techniques. One way is to provide them with synonyms, such as pointing out that a car is also called an automobile. Another important teaching tool is categorizing-showing the child that an item belongs to a larger class of items. With this technique, a child could be told that cars, buses, trucks, and bicycles are all vehicles, machines that carry people and things from place to place.

Because XXY boys have difficulty expressing themselves, they may do poorly on essay-style test questions. Multiple choice questions will give teachers a better idea of what an XXY child has learned-and prove less stressful for him as well. Similarly, rather than asking an open-ended question, parents and teachers may wish to present alternatives. Instead of asking "What would you 'like to do now?" they may wish to offer a choice: "Would you rather work on your spelling or work on your math?"

Parents and teachers can help XXY boys develop the ability to express themselves through solicited dialogue engaging them in conversation through a series of questions. The same technique can be used to get the child to develop his narrative (storytelling) abilities. For example, a parent might begin by asking a child what he did at recess that day, and by following up with questions that get the child to talk about his activities: "Did you go down the slide? Were you afraid when you climbed all the way to the top of the ladder? And then what? Did you go on the seesaw? Who sat on the other end?"

Parents can also help XXY boys develop their expressive language abilities simply by providing good examples. Through a technique known as modeling, they can help organize their children's thoughts and provide them with examples of how to express oneself. For instance, if a younger child indicated that he wanted a toy fire engine by pointing at it and grunting, the parent could hand it to him while saying "Here you are. This is a fire engine." Similarly, if an older child asked "Are we going to put the stuff in the thing?", the parent might reply "Yes, we're going to put the oranges in the shopping cart."

Research indicates that XXY boys may do poorly in an open classroom situation and seem to prefer a structured, tightly organized environment centered around familiar routines. First, teachers can reduce distraction by placing them in front row seats. Teachers also should present information slowly and repeat key points several times, if necessary. XXY boys should not be given tasks that have many small steps. Rather, each step should be presented individually. On completion, the child may then be asked to work on the next item in the series.

As mentioned above, XXY boys may withdraw from material they find difficult and retreat into day dreaming. A teacher or parent should gently regain the child's attention and help him to focus again on the task at hand. Similarly, XXY boys may have difficulty putting one task aside and beginning another one. Again, the parent or teacher should gently shift the child's attention, by saying something like "Drawing time is over. Let's put away the crayons and take out the math book."


In general, XXY boys enter puberty normally, without any delay of physical maturity. But as puberty progresses, they fail to keep pace with other males. In chromosomally normal teenaged boys, the testes gradually increase in size, from an initial volume of about 2 ml, to about 15 ml. In XXY males, while the penis is usually of normal size, the testes remain at 2 ml, and cannot produce sufficient quantities of the male hormone testosterone. As a result, many XXY adolescents, although taller than average, may not be as strong as other teenaged boys, and may lack facial or body hair.

As they enter puberty, many boys will undergo slight breast enlargement. For most teenaged males, this condition, known as gynecomastia, tends to disappear in a short time. About one-third of XXY boys develop enlarged breasts in early adolescence slightly more than do chromosomally normal boys. Furthermore, in XXY boys, this condition may be permanent. However, only about 10 percent of XXY males have breast enlargement great enough to require surgery.

Most XXY adolescents benefit from receiving an injection of testosterone every 2 weeks, beginning at puberty. The hormone increases strength and brings on a more muscular, masculine appearance. More information about testosterone and XXY males can be found in the section titled "Testosterone Treatment."

Adolescence and the high school years can be difficult for XXY boys and their families, particularly in neighborhoods and schools where the emphasis is on athletic ability and physical prowess.

Lack of strength and agility, combined with a history of learning disabilities, may damage self-esteem. Unsympathetic peers, too, sometimes may make matters worse, through teasing or ridicule.

Damage to self esteem may be more severe in XXY teenagers who are diagnosed in early or late adolescence. Teachers-and even parents-may have dismissed their scholastic difficulties as laziness. Lack of athletic prowess and the inability to use language properly in social settings may have helped to isolate them from their peers. Some may react by sliding quietly into depression and withdraw from contact with other people. Others may find acceptance in a dangerous crowd.

For these reasons, XXY males diagnosed as teenagers may need psychological counseling as well as help in overcoming their learning disabilities. Help with learning disabilities is available through public school systems for XXY males high-school age and under. Referrals to qualified mental health specialists may be obtained from family physicians.

Testosterone Treatment for Klinefelter Syndrome

Ideally, XXY males should begin testosterone treatment as they enter puberty. XXY males diagnosed in adulthood are also likely to benefit from the hormone. A regular schedule of testosterone injections will increase strength and muscle size, and promote the growth of facial and body hair.

In addition to these physical changes, testosterone injections often bring on psychological changes as well. As they begin to develop a more masculine appearance, the self-confidence of XXY males tends to increase. Many become more energetic and stop having sudden, angry changes in moods. What is not clear is whether these psychological changes are a direct result of testosterone treatment or are a side benefit of the increased self confidence that the treatment may bring. As a group, XXY boys tend to suffer from depression, principally because of their scholastic difficulties and problems fitting in with other males their age. Sudden, angry changes in mood are typical of depressed people.

Other benefits of testosterone treatment may include decreased need for sleep, an enhanced ability to concentrate, and improved relations with others. But to obtain these benefits an XXY male must decide, on his own, that he is ready to stick to a regular schedule of injections.

Sometimes, younger adolescents, who may be somewhat immature, seem not quite ready to take the shots. It is an inconvenience, and many don't like needles.

Most physicians do not push the young-men to take the injections. Instead, they usually recommend informing XXY adolescents and their parents about the benefits of testosterone injections and letting them take as much time as they need to make their decision.

Individuals may respond to testosterone treatment in different ways. Although the majority of XXY males ultimately will benefit from testosterone, a few will not.

To ensure that the injections will provide the maximum benefit, XXY males who are ready to begin testosterone injections should consult a qualified endocrinologist (a specialist in hormonal interactions) who has experience treating XXY males.

Side effects of the injections are few. Some individuals may develop a minor allergic reaction at the injection site, resulting in an itchy welt resembling a mosquito bite. Applying a non-prescription hydrocortisone cream to the area will reduce swelling and itching.

In addition, testosterone injections may result in a condition known as benign prostatic hyperplasia (BPH). This condition is common in chromosomally normal males as well, affecting more than 50 percent of men in their sixties, and as many as 90 percent in their seventies and eighties. In XXY males receiving testosterone injections, this condition may begin sometime after age 40.

The prostate is a small gland about the size of a walnut, which helps to manufacture semen. The gland is located just beneath the bladder and surrounds the urethra, the tube through which urine passes out of the body.

In BPH, the prostate increases in size, sometimes squeezing the bladder and urethra and causing difficulty urinating, "dribbling" after urination, and the need to urinate frequently.

XXY males receiving testosterone injections should consult their physicians about a regular schedule of prostate examinations. BPH can often be detected early by a rectal exam. If the prostate greatly interferes with the flow of urine, excess prostate tissue can be trimmed away by a surgical instrument that is inserted in the penis, through the urethra.

Chromosomal Variations

Occasionally, variations of the XXY chromosome count may occur, the most common being the XY/XXY mosaic. In this variation, some of the cells in the male's body have an additional X chromosome, and the rest have the normal XY chromosome count. The percentage of cells containing the extra chromosome varies from case to case. In some instances, XY/XXY mosaics may have enough normally functioning cells in the testes to allow them to father children.

A few instances of males having two or even three additional X chromosomes have also been reported in the medical literature. In these individuals, the classic features of Klinefelter syndrome may be exaggerated, with low I.Q. or moderate to severe mental retardation also occurring.

In rare instances, an individual may possess both an additional X and an additional Y chromosome. The medical literature describes XXYY males as having slight to moderate mental retardation. They may sometimes be aggressive or even violent. Although they may have a rounded body type and decreased sex drive, experts disagree whether testosterone injections are appropriate for all of them.

However, that because these cases are so rare, not much is known about them. Most of the XXYY males who have been studied were referred to treatment because they were violent and got into trouble with the law. It is not known whether XXYY males are inherently aggressive by nature, or whether only a few extreme individuals come to the attention of researchers precisely because they are aggressive.


The parents of XXY boys are sometimes concerned that their sons may grow up to be homosexual. This concern is unfounded, however, as there is no evidence that XXY males are any more inclined toward homosexuality than are other men.

In fact, the only significant sexual difference between XXY men and teenagers and other males their age is that the XXY males may have less interest in sex. However, regular injections of the male sex hormone testosterone can bring sex drive up to normal levels.

In some cases, testosterone injections lead to a false sense of security: After receiving the hormone for a time, XXY males may conclude they've derived as much benefit from it as possible and discontinue the injections. But when they do, their interest in sex almost invariably diminishes until they resume the injections.


The vast majority of XXY males do not produce enough sperm to allow them to become fathers. If these men and their wives wish to become parents, they should seek counseling from their family physician regarding adoption and infertility.

However, no XXY male should automatically assume he is infertile without further testing. In a very small number of cases, XXY males have been able to father children.

In addition, a few individuals who believe themselves to be XXY males may actually be XY/XXY mosaics. Along with having cells with the XXY chromosome count, these males may also have cells with the normal XY chromosome count. If the number of XY cells in the testes is great enough, the individual should be able to father children.

Karyotyping, the method traditionally used to identify an individual's chromosome count, may sometimes fail to identify XY/ XXY mosaics. For this reason, a karyotype should never be used to predict whether an individual will be infertile or not.

Health Considerations

Compared with other males, XXY males have a slightly increased risk of autoimmune disorders. In this group of diseases, the immune system, for unknown reasons, attacks the body's organs or tissues. The most well known of these diseases are type I (insulin dependent) diabetes, autoimmune thyroiditis, and lupus erythematosus. Most of these conditions can be treated with medication.

XXY males with enlarged breasts have the same risk of breast cancer as do women-roughly 50 times the risk XY males have. For this reason, these XXY adolescents and men need to practice regular breast self examination. The free booklet Breast Exams: What You Should Know is available from the National Cancer Institute, listed in the Resources section. The last page of the booklet is a pullout chart listing the instructions for breast self examination. Although the booklet was written primarily for women, the breast self examination technique also can be used by XXY males. XXY males may also wish to consult their physicians about the need for more thorough breast examinations by medical professionals.

In addition, XXY males who do not receive testosterone injections may have an increased risk of developing osteoporosis in later life. In this condition, which usually afflicts women after the age of menopause, the bones lose calcium, becoming brittle and more likely to break.


Unfortunately, comparatively little is known about XXY adults. Studies in the United States have focused largely on XXY males identified in infancy from large random samples. Only a few of these individuals have reached adulthood; most are still in adolescence. At this time, researchers simply do not know what kind of adults they will become.

Comparatively few studies of XXY males diagnosed in adulthood have been conducted. By and large, the men who took part in these studies were not selected at random but identified by a particular characteristic, such as height. For this reason, it is not known whether these individuals are truly representative of XXY men as a whole or represent a particular extreme.

One study found a group of XXY males diagnosed between the ages of 27 and 37 to have suffered a number of setbacks, in comparison to a similar group of XY males. The XXY men were more likely to have had histories of scholastic failure, depression and other psychological problems, and to lack energy and enthusiasm.

But by the time the XXY men had reached their forties, most had surmounted their problems. The majority said that their energy and activity levels had increased, that they were more productive on the job, and that their relationships with other people had improved. In fact, the only difference between the XY males and the XXY males was that the latter were less likely to have been married.

That these men eventually overcame their troubled pasts is encouraging for all XXY males and particularly encouraging for those diagnosed in childhood. Had they received counseling, support, and testosterone treatments beginning in childhood, these men might have avoided the difficulties of their twenties and thirties.

Although a supportive environment through childhood and adolescence appears to offer the greatest chance for a well-adjusted adulthood, it is not too late for XXY men diagnosed as adults to seek help.

Research has shown that testosterone injections, begun in adulthood, can be beneficial. Psychological counseling also offers the best hope of overcoming depression and other psychological problems. For referrals to endocrinologists qualified to administer testosterone or to mental health specialists, XXY men should consult their physicians.