The third indicator is the presence of clues to specific disorders of the reproductive system.

- Malnutrition or anorexia nervosa severe enough to delay puberty will give other clues as well.

- Poor growth would suggest the possibility of coeliac disease, hypopituitarism or Turner syndrome.

- Reduced sense of smell (hyposmia) or no sense of smell (anosmia) suggests Kallmann syndrome.

The first is simply degree of lateness: although no recommended age of evaluation cleanly separates pathologic from physiologic delay, a delay of 2–3 years or more warrants evaluation.

- In girls, no breast development by 13 years, or no menarche by 3 years after breast development (or by 16).

- In boys, no testicular enlargement by 14 years, or delay in development for 5 years or more after onset of genitalia enlargement.

A delay of two standard deviations has been proposed as a standard.

Early puberty is believed to put girls at higher risk of sexual abuse, unrelated to pedophilia because the child has developed secondary sex characteristics; however, a causal relationship is, as yet, inconclusive. Early puberty also puts girls at a higher risk for teasing or bullying, mental health disorders and short stature as adults. Helping children control their weight is suggested to help delay puberty. Early puberty additionally puts girls at a "far greater" risk for breast cancer later in life. Girls as young as 8 are increasingly starting to menstruate, develop breasts and grow pubic and underarm hair; these "biological milestones" typically occurred only at 13 or older in the past. African-American girls are especially prone to early puberty. There are theories debating the trend of early puberty, but the exact causes are not known.

Though boys face fewer problems upon early puberty than girls, early puberty is not always positive for boys; early sexual maturation in boys can be accompanied by increased aggressiveness due to the surge of hormones that affect them. Because they appear older than their peers, pubescent boys may face increased social pressure to conform to adult norms; society may view them as more emotionally advanced, although their cognitive and social development may lag behind their appearance. Studies have shown that early maturing boys are more likely to be sexually active and are more likely to participate in risky behaviours.

Conditions justifying newborn screening for any disorder include (1) a simple test with an acceptable sensitivity and specificity, (2) a dire consequence if not diagnosed early, (3) an effective treatment if diagnosed, and (4) a frequency in the population high enough to justify the expense. In the last decade more states and countries are adopting newborn screening for salt-wasting CAH due to 21-hydroxylase deficiency, which leads to death in the first month of life if not recognized.

The salt-wasting form of CAH has an incidence of 1 in 15,000 births and is potentially fatal within a month if untreated. Steroid replacement is a simple, effective treatment. However, the screening test itself is less than perfect. While the 17α-hydroxyprogesterone level is easy to measure and sensitive (rarely missing real cases), the test has a poorer specificity. Screening programs in the United States have reported that 99% of positive screens turn out to be false positives upon investigation of the infant. This is a higher rate of false positives than the screening tests for many other congenital metabolic diseases.

When a positive result is detected, the infant must be referred to a pediatric endocrinologist to confirm or disprove the diagnosis. Since most infants with salt-wasting CAH become critically ill by 2 weeks of age, the evaluation must be done rapidly despite the high false positive rate.

Levels of 17α-hydroxyprogesterone, androstenedione, and cortisol may play a role in screening.

The diagnosis is often one of exclusion found during the workup of delayed puberty.

A paper published in 2012 by Prof. Jacques Young highlights a typical example of the diagnostic work up involved in a suspected case of KS/CHH.

One of the biggest problems in the diagnosis of KS and other forms of CHH is the ability to distinguish between a normal constitutional delay of puberty and KS or CHH.

The main biochemical parameters in men are low serum testosterone and low levels of the gonadotropins LH and FSH, and in women low serum oestrogen and low levels of LH and FSH.

For both males and females with constitutional delay of puberty, endogenous puberty will eventually commence without treatment. However a delay in treatment in a case of KS/HH will delay the physical development of the patient and can cause severe psychological damage. The "wait and see" approach applied to "late bloomers" is probably counterproductive to the needs of the patient whereas a step-by-step approach with hormone replacement therapy used with slowly increasing doses can be used as a diagnostic tool.

Post natal diagnosis of KS / CHH before the age of 6 months is sometimes possible. The normal post natal hormonal surge of gonadotropins along with testosterone or oestrogen is absent in babies with KS / CHH. This lack of detectable hormones in the blood can be used as a diagnostic indicator, especially in male infants.

Normally testicular enlargement is the key sign for the onset of puberty in boys however the use of nighttime LH sampling can help predict the onset of puberty.

In females diagnosis is sometimes further delayed as other causes of amenorrhoea normally have to be investigated first before a case of KS/CHH is considered. KS/CHH can still occur in females in cases when menstruation has begun but stopped after one or two menstrual bleeds. A study of GnRH deficient women in 2011 showed that 10% had experienced one or two bleeds before the onset of amenorrhoea.

In males, treatment with age-appropriate levels of testosterone can be used to distinguish between a case of KS/CHH from a case of delayed puberty. If just delayed the testosterone can "kick-start" endogenous puberty, as demonstrated by testicular enlargement, whereas in the case of KS/CHH there will be no testicular enlargement while on testosterone therapy alone. If no puberty is apparent, especially no testicular development, then a review by a reproductive endocrinologist may be appropriate. Dr Richard Quinton, a leading UK expert on KS/CHH, suggests that if puberty is not apparent by the age of 16 then the patient should be referred for endocrinological review.

A full endocrine workup will be required to measure the levels of the other pituitary hormones, especially prolactin, to check that the pituitary gland is working correctly. There can be other general health issues such as being overweight or having an underlying chronic or acute illness which could cause a delay of puberty. This makes it essential for a patient to get a full endocrine review to distinguish between a case of KS/CHH and another cause for the pubertal delay.

Bone age can be assessed using hand and wrist X-rays. If the bone age is significantly lower than the chronological age of the patient, this could suggest delayed puberty unless there is another underlying reason for the discrepancy.

A karyotype may be performed to rule out Klinefelter syndrome and Turner syndrome, although the hormones levels would also rule out both these relatively common reasons for hypogonadism.

A magnetic resonance imaging (MRI) scan can be used to determine whether the olfactory bulb is present and to check for any physical irregularities of the pituitary gland or hypothalamus.

A standard smell test can be used to check for anosmia, but it must be remembered that even in total anosmia various substances (such as menthol and alcohol) can still be detected by direct stimulation of the trigeminal nerve.

Genetic screening can be carried out, but in light of the unknown genes involved in the majority of KS and CHH cases, a negative result will not rule out a possible diagnosis.

A review paper published in 2014 highlighted the need for doctors to be aware of the possible diagnosis of KS / HH if pubertal delay is found alongside associated "red flag" symptoms. The symptoms listed in the paper were split into two categories; reproductive symptoms associated with the lack of mini puberty seen between birth and six months of age and non-reproductive symptoms which are associated with specific forms of HH. As with other review papers the authors also warned against the "wait and see" approach when puberty appears to be delayed.

Studies indicate that breast development in girls and the appearance of pubic hair in girls and boys are starting earlier than in previous generations. As a result, "early puberty" in children, particularly girls, as young as 9 and 10 is no longer considered abnormal, although it may be upsetting to parents and can be harmful to children who mature physically at a time when they are immature mentally.

No age reliably separates normal from abnormal processes in children, but the following age thresholds for evaluation are thought to minimize the risk of missing a significant medical problem:

- Breast development in boys before appearance of pubic hair or testicular enlargement,

- Pubic hair or genital enlargement (gonadarche) in boys with onset before 9.5 years,

- Pubic hair (pubarche) before 8 or breast development (thelarche) in girls with onset before 7 years,

- Menstruation (menarche) in girls before 10 years.

Medical evaluation is sometimes necessary to recognize the few children with serious conditions from the majority who have entered puberty early but are still medically normal. Early sexual development warrants evaluation because it may:

- induce early bone maturation and reduce eventual adult height,

- indicate the presence of a tumour or other serious problem,

- cause the child, particularly a girl, to become an object of adult sexual interest.

Since CAH is an autosomal recessive disease, most children with CAH are born to parents unaware of the risk and with no family history. Each child will have a 25% chance of being born with the disease. Families typically wish to minimize the degree of virilization of a girl. There is no known prenatal harm to a male fetus from CAH, so treatment can begin at birth.

Adrenal glands of female fetuses with CAH begin producing excess testosterone by the 9th week of gestation. The most important aspects of virilization (urogenital closure and phallic urethra) occur between 8 and 12 weeks. Theoretically, if enough glucocorticoid could be supplied to the fetus to reduce adrenal testosterone production by the 9th week, virilization could be prevented and the difficult decision about timing of surgery avoided.

The challenge of preventing severe virilization of girls is twofold: detection of CAH at the beginning of the pregnancy, and delivery of an effective amount of glucocorticoid to the fetus without causing harm to the mother.

The first problem has not yet been entirely solved, but it has been shown that if dexamethasone is taken by a pregnant woman, enough can cross the placenta to suppress fetal adrenal function.

At present no program screens for risk in families who have not yet had a child with CAH. For families desiring to avoid virilization of a second child, the current strategy is to start dexamethasone as soon as a pregnancy has been confirmed even though at that point the chance that the pregnancy is a girl with CAH is only 12.5%. Dexamethasone is taken by the mother each day until it can be safely determined whether she is carrying an affected girl.

Whether the fetus is an affected girl can be determined by chorionic villus sampling at 9–11 weeks of gestation, or by amniocentesis at 15–18 weeks gestation. In each case the fetal sex can be determined quickly, and if the fetus is a male the dexamethasone can be discontinued. If female, fetal DNA is analyzed to see if she carries one of the known abnormal alleles of the "CYP21" gene. If so, dexamethasone is continued for the remainder of the pregnancy at a dose of about 1 mg daily.

Most mothers who have followed this treatment plan have experienced at least mild cushingoid effects from the glucocorticoid but have borne daughters whose genitalia are much less virilized.

Currently, in the United States and over 40 other countries, every child born is screened for 21-hydroxylaase CAH at birth. This test will detect elevated levels of 17-hydroxy-progesterone (17-OHP). Detecting high levels of 17-OHP enables early detection of CAH. Newborns detected early enough can be placed on medication and live a relatively normal life.

The screening process, however, is characterized by a high false positive rate. In one study, CAH screening had the lowest positive predictive value (111 true-positive cases among 20,647 abnormal screening results in a 2-year period, or 0.53%, compared with 6.36% for biotinidase deficiency, 1.84% for congenital hypo-thyroidism, 0.56% for classic galactosemia, and 2.9% for phenylketonuria). According to this estimate, 200 unaffected newborns required clinical and laboratory follow-up for every true case of CAH.

CAIS can only be diagnosed in normal phenotypic females. It is not usually suspected unless the menses fail to develop at puberty, or an inguinal hernia presents during premenarche. As many as 1–2% of prepubertal girls that present with an inguinal hernia will also have CAIS.

A diagnosis of CAIS or Swyer syndrome can be made in utero by comparing a karyotype obtained by amniocentesis with the external genitalia of the fetus during a prenatal ultrasound. Many infants with CAIS do not experience the normal, spontaneous neonatal testosterone surge, a fact which can be diagnostically exploited by obtaining baseline luteinizing hormone and testosterone measurements, followed by a human chorionic gonadotropin (hGC) stimulation test.

The main differentials for CAIS are complete gonadal dysgenesis (Swyer syndrome) and Müllerian agenesis (Mayer-Rokitansky-Kuster-Hauser syndrome or MRKH). Both CAIS and Swyer syndrome are associated with a 46,XY karyotype, whereas MRKH is not; MRKH can thus be ruled out by checking for the presence of a Y chromosome, which can be done either by fluorescence in situ hybridization (FISH) analysis or on full karyotype. Swyer syndrome is distinguished by poor breast development and shorter stature. The diagnosis of CAIS is confirmed when androgen receptor (AR) gene sequencing reveals a mutation, although up to 5% of individuals with CAIS do not have an AR mutation.

Up until the 1990s, a CAIS diagnosis was often hidden from the affected individual and / or family. It is current practice to disclose the genotype at the time of diagnosis, particularly when the affected girl is at least of adolescent age. If the affected individual is a child or infant, it is generally up to the parents, often in conjunction with a psychologist, to decide when to disclose the diagnosis.

Individuals with CAIS are raised as females. They are born phenotypically female and almost always have a heterosexual female gender identity; the incidence of homosexuality in women with CAIS is thought to be less than unaffected women. However, at least two case studies have reported male gender identity in individuals with CAIS.

Treatment of HH may consist of administration of either a GnRH agonist or a gonadotropin formulation in the case of primary HH and treatment of the root cause (e.g., a tumor) of the symptoms in the case of secondary HH. Alternatively, hormone replacement therapy with androgens and estrogens in males and females, respectively, may be employed.

Hormone replacement therapy with estrogen may be used to treat symptoms of hypoestrogenism in females with the condition. There are currently no known treatments for the infertility caused by the condition in either sex.

Treatment for KS and other forms of HH can be divided into hormone replacement therapy and fertility treatments.

During pregnancy, the placenta, which is fetal tissue, synthesizes large amounts of estrogen. The levels of estrogen in the mother can elevate 100-fold higher than normal cycling levels. In fetal aromatase deficiency, the placenta synthesizes the intermediates in the biosynthesis of the estrogens, androstenedione and testosterone, but cannot convert them the rest of the way due to the absence of aromatase. These compounds, which are androgens, subsequently accumulate to high levels and circulate, severely masculinizing both the fetus and the mother. The mother will experience cystic acne, hirsutism, deepening of the voice, and clitoromegaly, which will partially reverse following parturition. The fetus, if female, will be born with severely masculinized external genitalia, including labioscrotal fusion and a greatly enlarged phallus. A male fetus will be born with normal genitalia.

At puberty, due to the lack of aromatase, estrogens will not be synthesized by the ovaries, and normal puberty, including breast development and the onset of menses, will not occur. Instead, androgens will elevate once again above normal levels, and may cause additional virilization, such as acne, hirsutism, and further enlargement of the clitoris, unless treatment with estrogen is given.

Aromatase deficiency in the baby can also affect the mother during gestation, with cystic acne, hirsutism, deepening of the voice, and clitoromegaly. Increased circulating testosterone levels are the cause. The mother's symptoms resolve after she gives birth.

Gonadectomy at time of diagnosis is the current recommendation for PAIS if presenting with cryptorchidism, due to the high (50%) risk of germ cell malignancy. The risk of malignancy when testes are located intrascrotally is unknown; the current recommendation is to biopsy the testes at puberty, allowing investigation of at least 30 seminiferous tubules, with diagnosis preferably based on OCT3/4 immunohistochemistry, followed by regular examinations. Hormone replacement therapy is required after gonadectomy, and should be modulated over time to replicate the hormone levels naturally present in the body during the various stages of puberty. Artificially induced puberty results in the same, normal development of secondary sexual characteristics, growth spurt, and bone mineral accumulation. Women with PAIS may have a tendency towards bone mineralization deficiency, although this increase is thought to be less than is typically seen in CAIS, and is similarly managed.

Genetic analysis can be helpful to confirm a diagnosis of CAH but it is not necessary if classic clinical and laboratory findings are present.

In classic 21-hydroxylase deficiency, laboratory studies will show:

Classic 21-hydroxylase deficiency typically causes 17α-hydroxyprogesterone blood levels >242 nmol/L. (For comparison, a full-term infant at three days of age should have <3 nmol/L. Many neonatal screening programs have specific reference ranges by weight and gestational age because high levels may be seen in premature infants without CAH.) Salt-wasting patients tend to have higher 17α-hydroxyprogesterone levels than non-salt-wasting patients. In mild cases, 17α-hydroxyprogesterone may not be elevated in a particular random blood sample, but it will rise during a corticotropin stimulation test.

Unfortunately, the number of differentials to consider for PAIS is particularly large. Prompt diagnosis is particularly urgent when a child is born with ambiguous genitalia, as some causes are associated with potentially life-threatening adrenal crises. Determination of testosterone, testosterone precursors and dihydrotestosterone (DHT) at baseline and / or after human chorionic gonadotropin (hCG) stimulation can be used to exclude such defects in androgen biosynthesis.

Approximately one half of all 46,XY individuals born with ambiguous genitalia will not receive a definitive diagnosis. Androgen receptor (AR) gene mutations cannot be found in 27% to 72% of individuals with PAIS. As a result, genetic analysis can be used to confirm a diagnosis of PAIS, but it cannot be used to rule out PAIS. Evidence of abnormal androgen binding in a genital skin fibroblast study has long been the gold standard for the diagnosis of PAIS, even when an AR mutation is not present. However, some cases of PAIS, including AR-mutant-positive cases, will show normal androgen binding. A family history consistent with X-linked inheritance is more commonly found in AR-mutant-positive cases than AR-mutant-negative cases.

The use of dynamic endocrine tests is particularly helpful in isolating a diagnosis of PAIS. One such test is the human chorionic gonadotropin (hCG) stimulation test. If the gonads are testes, there will be an increase in the level of serum testosterone in response to the hCG, regardless of testicular descent. The magnitude of the testosterone increase can help differentiate between androgen resistance and gonadal dysgenesis, as does evidence of a uterus on ultrasound examination. Testicular function can also be assessed by measuring serum anti-Müllerian hormone levels, which in turn can further differentiate PAIS from gonadal dysgenesis and bilateral anorchia.

Another useful dynamic test involves measuring the response to exogenous steroids; individuals with AIS show a decreased response in serum sex hormone binding globulin (SHBG) after a short term administration of anabolic steroids. Two studies indicate that measuring the response in SHBG after the administration of stanozolol could help to differentiate individuals with PAIS from those with other causes of ambiguous genitalia, although the response in individuals with predominantly male phenotypes overlaps somewhat with the response in normal males.

Since the Sertoli cells are not affected by Leydig cell hypoplasia, anti-Müllerian hormone is secreted normally and so there are no Müllerian structures. Wolffian structures, such as the prostate, vasa deferentia, and epidydimides are present. In type I, abdominal testes are revealed on ultrasound; in type II testes may be descended or undescended.

People with Leydig cell hypoplasia type I display no response to the hCG stimulation test; there is no increase in serum levels of testosterone and dihydrotestosterone. Leydig cell hypoplasia type II can display either a pronounced rise of testosterone levels or no rise.

In any case, the diagnosis is confirmed on biopsy of the testes, revealing either absent or hypoplastic Leydig cells. The inside of the testis will be grayish and mucous, displaying arrested spermatogenesis and the presence of Sertoli cells. The diagnosis can also be confirmed by looking for mutations in the gene for the LH receptor.

A diagnosis of Leydig cell hypoplasia is usually made in the neonatal period, following the discovery of ambiguous genitalia, or at puberty, when secondary sex characteristics fail to develop. Puberty is the most common time for Leydig cell hypoplasia to be diagnosed.

Patients with Leydig cell hypoplasia may be treated with hormone replacement therapy (i.e., with androgens), which will result in normal sexual development and the resolution of most symptoms. In the case of 46,XY (genetically "male") individuals who are phenotypically female and/or identify as the female gender, estrogens should be given instead. Surgical correction of the genitals in 46,XY males may be required, and, if necessary, an orchidopexy (relocation of the undescended testes to the scrotum) may be performed as well.

Due to the inability of the streak gonads to produce sex hormones (both estrogens and androgens), most of the secondary sex characteristics do not develop. This is especially true of estrogenic changes such as breast development, widening of the pelvis and hips, and menstrual periods. As the adrenal glands can make limited amounts of androgens and are not affected by this syndrome, most of these persons will develop pubic hair, though it often remains sparse.

Evaluation of delayed puberty usually reveals elevation of gonadotropins, indicating that the pituitary is providing the signal for puberty but the gonads are failing to respond. The next steps of the evaluation usually include checking a karyotype and imaging of the pelvis. The karyotype reveals XY chromosomes and the imaging demonstrates the presence of a uterus but no ovaries (the streak gonads are not usually seen by most imaging). Although an XY karyotype can also indicate a person with complete androgen insensitivity syndrome, the absence of breasts, and the presence of a uterus and pubic hair exclude the possibility. At this point it is usually possible for a physician to make a diagnosis of Swyer syndrome.

Several treatments have been found to be effective in managing AES, including aromatase inhibitors and gonadotropin-releasing hormone analogues in both sexes, androgen replacement therapy with non-aromatizable androgens such as DHT in males, and progestogens (which, by virtue of their antigonadotropic properties at high doses, suppress estrogen levels) in females. In addition, male patients often seek bilateral mastectomy, whereas females may opt for breast reduction if warranted.

Medical treatment of AES is not absolutely necessary, but it is recommended as the condition, if left untreated, may lead to excessively large breasts (which may necessitate surgical reduction), problems with fertility, and an increased risk of endometriosis and estrogen-dependent cancers such as breast and endometrial cancers later in life. At least one case of male breast cancer has been reported.

Males and females may be treated with hormone replacement therapy (i.e., with androgens and estrogens, respectively), which will result in normal sexual development and resolve most symptoms. In the case of 46,XY (genetically male) individuals who are phenotypically female and/or identify as the female gender, they should be treated with estrogens instead. Removal of the undescended testes should be performed in 46,XY females to prevent their malignant degeneration, whereas in 46,XY males surgical correction of the genitals is generally required, and, if necessary, an orchidopexy (relocation of the undescended testes to the scrotum) may be performed as well. Namely in genetic females presenting with ovarian cysts, GnRH analogues may be used to control high FSH and LH levels if they are unresponsive to estrogens.

The syndrome usually responds well to thyroid hormone replacement with complete resolution of symptoms.

Treatment of HH is usually with hormone replacement therapy, consisting of androgen and estrogen administration in males and females, respectively.