All forms of androgen insensitivity are associated with infertility, though exceptions have been reported for both the mild and partial forms. Lifespan is not thought to be affected by AIS.

Due to its mild presentation, MAIS often goes unnoticed and untreated. Management of MAIS is currently limited to symptomatic management; methods to correct a malfunctioning androgen receptor protein that result from an AR gene mutation are not currently available. Treatment includes surgical correction of mild gynecomastia, minor hypospadias repair, and testosterone supplementation. Supraphysiological doses of testosterone have been shown to correct diminished secondary sexual characteristics in men with MAIS, as well as to reverse infertility due to low sperm count. As is the case with PAIS, men with MAIS will experience side effects from androgen therapy (such as the suppression of the hypothalamic-pituitary-gonadal axis) at a higher dosage than unaffected men. Careful monitoring is required to ensure the safety and efficacy of treatment. Regular breast and prostate examinations may be necessary due to comorbid association with breast and prostate cancers.

This syndrome, evenly spread in all ethnic groups, has a prevalence of 1-2 subjects per every 1000 males in the general population. 3.1% of infertile males have Klinefelter syndrome. The syndrome is also the main cause of male hypogonadism.

According to 2008 meta-analysis, the prevalence of the syndrome has increased over the past decades; however, this does not appear to be related to increased age of the mother at conception, as no increase was observed in the rates of other trisomies of sex chromosomes (XXX and XYY). The National Institutes of Health; however, state that older mothers might have a slightly increased risk.

In most full-term infant boys with cryptorchidism but no other genital abnormalities, a cause cannot be found, making this a common, sporadic, unexplained (idiopathic) birth defect. A combination of genetics, maternal health, and other environmental factors may disrupt the hormones and physical changes that influence the development of the testicles.

- Severely premature infants can be born before descent of testes. Low birth weight is also a known factor.

- A contributing role of environmental chemicals called endocrine disruptors that interfere with normal fetal hormone balance has been proposed. The Mayo Clinic lists "parents' exposure to some pesticides" as a known risk factor.

- Diabetes and obesity in the mother.

- Risk factors may include exposure to regular alcohol consumption during pregnancy (5 or more drinks per week, associated with a 3x increase in cryptorchidism, when compared to non-drinking mothers. Cigarette smoking is also a known risk factor.

- Family history of undescended testicle or other problems of genital development.

- Cryptorchidism occurs at a much higher rate in a large number of congenital malformation syndromes. Among the more common are Down syndrome Prader–Willi syndrome, and Noonan syndrome.

- In vitro fertilization, use of cosmetics by the mother, and preeclampsia have also been recognized as risk factors for development of cryptorchidism.

In 2008 a study was published that investigated the possible relationship between cryptorchidism and prenatal exposure to a chemical called phthalate (DEHP) which is used in the manufacture of plastics. The researchers found a significant association between higher levels of DEHP metabolites in the pregnant mothers and several sex-related changes, including incomplete descent of the testes in their sons. According to the lead author of the study, a national survey found that 25% of U.S. women had phthalate levels similar to the levels that were found to be associated with sexual abnormalities.

A 2010 study published in the European medical journal "Human Reproduction" examined the prevalence of congenital cryptorchidism among offspring whose mothers had taken mild analgesics, primarily over-the-counter pain medications including ibuprofen (e.g. Advil) and paracetamol (acetaminophen). Combining the results from a survey of pregnant women prior to their due date in correlation with the health of their children and an "ex vivo" rat model, the study found that pregnant women who had been exposed to mild analgesics had a higher prevalence of baby boys born with congenital cryptorchidism.

New insight into the testicular descent mechanism has been hypothesized by the concept of a male programming window (MPW) derived from animal studies. According to this concept, testicular descent status is "set" during the period from 8 to 14 weeks of gestation in humans. Undescended testis is a result of disruption in androgen levels only during this programming window.

Children with XXY differ little from other children. Although they can face problems during adolescence, often emotional and behavioral, and difficulties at school, most of them can achieve full independence from their families in adulthood. Most can lead a normal, healthy life.

The results of a study carried out on 87 Australian adults with the syndrome shows that those who have had a diagnosis and appropriate treatment from a very young age had a significant benefit with respect to those who had been diagnosed in adulthood.

There is research suggesting Klinefelter syndrome substantially decreases life expectancy among affected individuals, though the evidence is not definitive. A 1985 publication identified a greater mortality mainly due to diseases of the aortic valve, development of tumors and possible subarachnoid hemorrhages, reducing life expectancy by about 5 years. Later studies have reduced this estimated reduction to an average of 2.1 years. These results are still questioned data, are not absolute, and will need further testing.

Spermatogenesis arrest is a complex process of interruption in the differentiation of germinal cells of specific cellular type, which elicits an altered spermatozoa formation. Spermatogenic arrest is usually due to genetic factors resulting in irreversible azoospermia. However some cases may be consecutive to hormonal, thermic, or toxic factors and may be reversible either spontaneously or after a specific treatment.

One of the strongest arguments for early orchiopexy is reducing the risk of testicular cancer. About 1 in 500 men born with one or both testes undescended develops testicular cancer, roughly a 4 to 40 fold increased risk. The peak incidence occurs in the 3rd and 4th decades of life. The risk is higher for intra-abdominal testes and somewhat lower for inguinal testes, but even the "normally descended" testis of a man whose other testis was undescended has about a 20% higher cancer risk than those of other men.

The most common type of testicular cancer occurring in undescended testes is seminoma. It is usually treatable if caught early, so urologists often recommend that boys who had orchiopexy as infants be taught testicular self-examination, to recognize testicular masses and seek early medical care for them. Cancer developing in an intra-abdominal testis would be unlikely to be recognized before considerable growth and spread, and one of the advantages of orchiopexy is that a mass developing in a scrotal testis is far easier to recognize than an intra-abdominal mass.

It was originally felt that orchidopexy resulted in easier detection of testis cancer but did not lower the risk of actually developing cancer. However, recent data has resulted in a paradigm shift. The New England Journal of Medicine published in 2007 that orchidopexy performed before puberty resulted in a significantly reduced risk of testicular cancer than if done after puberty.

The risk of malignancy in the undescended testis is 4 to 10 times higher than that in the general population and is approximately 1 in 80 with a unilateral undescended testis and 1 in 40 to 1 in 50 for bilateral undescended testes. The peak age for this tumor is 15–45 yr. The most common tumor developing in an undescended testis is a seminoma (65%); in contrast, after orchiopexy, seminomas represent only 30% of testis tumors.

To some extent, it is possible to change testicular size. Short of direct injury or subjecting them to adverse conditions, e.g., higher temperature than they are normally accustomed to, they can be shrunk by competing against their intrinsic hormonal function through the use of externally administered steroidal hormones. Steroids taken for muscle enhancement (especially anabolic steroids) often have the undesired side effect of testicular shrinkage.

Similarly, stimulation of testicular functions via gonadotropic-like hormones may enlarge their size. Testes may shrink or atrophy during hormone replacement therapy or through chemical castration.

In all cases, the loss in testes volume corresponds with a loss of spermatogenesis.

Testicular size as a proportion of body weight varies widely. In the mammalian kingdom, there is a tendency for testicular size to correspond with multiple mates (e.g., harems, polygamy). Production of testicular output sperm and spermatic fluid is also larger in polygamous animals, possibly a spermatogenic competition for survival. The testes of the right whale are likely to be the largest of any animal, each weighing around 500 kg (1,100 lb).

Among the Hominidae, gorillas have little female promiscuity and sperm competition and the testes are small compared to body weight (0.03%). Chimpanzees have high promiscuity and large testes compared to body weight (0.3%). Human testicular size falls between these extremes (0.08%).

Testis weight also varies in seasonal breeders like deer and horses. The change is related to changes in testosterone production.

Human testicles are smaller than chimpanzee testicles but larger than gorilla testicles.

It is thought to have an estimated incidence of 1 in 75,000 people.

A prognosis for Alström syndrome is complicated because it widely varies. Any person that has the syndrome have different set of disorders. Permanent blindness, deafness, and Type 2 diabetes may occur. Liver and kidney failure can progressively get worse. The life expectancy is usually reduced and the patients rarely live past 50 years old.

Recent findings in genetic research have suggested that a large number of genetic disorders, both genetic syndromes and genetic diseases, that were not previously identified in the medical literature as related, may be, in fact, highly related in the genetypical root cause of the widely varying, phenotypically-observed disorders. Thus, Alstrom syndrome is a ciliopathy. Other known ciliopathies include primary ciliary dyskinesia, Bardet-Biedl syndrome, polycystic kidney and liver disease, nephronophthisis, Meckel-Gruber syndrome and some forms of retinal degeneration.

Ring chromosome 14 syndrome is extremely rare, the true rate of occurrence is unknown (as it is "less than" 1 per 1,000,000), but there are at least 50 documented cases in the literature.

Miller-Dieker occurs in less than one in 100000 people and can occur in all races.

Monosomy is a form of aneuploidy with the presence of only one chromosome (instead of the typical two in humans) from a pair, which affects chromosome 14. Fetuses with monosomy 14 are not viable. Only mosaic cases exist and these usually present with severe symptoms such as intellectual disability, ocular colobomata, microcephaly, and seizures.

Allen Avinoam Kowarski et al. described the first two cases of the Kowarski syndrome in 1978. The group speculated that their patients' growth impairment was caused by a mutation in the growth hormone gene, which altered the structure of their secreted growth hormone, reducing its biological activity while retaining its ability to bind the antibodies used in the RIA-GH. Their RIA-GH measured growth hormone of reduced bioactivity. The children retained the ability to respond to treatment with active growth hormone.

The speculation of Kowarski et al. was confirmed by Valenta et al in 1985, Takahshi et al in 1996 and 1997 and Besson et al in 2005. Valenta et al studied a case of Kowarski syndrome where they confirmed a structural abnormality of the growth hormone molecule. 60 to 90% of circulating growth hormone of the patient was in the form of tetramers and dimers (normal, 14% to 39% in plasma) and the patients' growth hormone polymers were abnormally resistant to conversion into monomers by urea.

Takahashi et al. reported a case of a boy with short stature who was heterozygous for a mutation in the GH1 gene. In this child, growth hormone not only could not activate the GH receptor (GHR) but also inhibited the action of wild type GH because of its greater affinity for GHR and GH-binding protein (GHBP) that is derived from the extracellular domain of the GHR. Thus, a dominant-negative effect was observed.

Takahashi et al. demonstrated in a girl with short stature, a biologically inactive growth hormone resulting from a heterozygous mutation in the GH1 gene. At age 3 years, the girl's height was 3.6 standard deviations below the mean for age and sex. Bone age was delayed by 1.5 years. She had a prominent forehead and a hypoplastic nasal bridge with normal body proportions. She showed lack of growth hormone action despite high immunoassayable GH levels in serum and marked catch-up growth to exogenous GH administration. Results of other studies were compatible with the production of a bioinactive GH, which prevented dimerization of the growth hormone receptor, a crucial step in GH signal transduction.

Besson et al described in 1955 a Serbian patient with Kowarski syndrome who was homozygous for a mutation in the GH1 gene that disrupted the first disulfide bridge in growth hormone. The parents were each heterozygous for the mutation and were of normal stature.

Jalili syndrome is a genetic disorder characterized by the combination of cone-rod dystrophy of the retina and amelogenesis imperfecta. It was characterized in 1988 by Dr. I. K. Jalili and Dr. N. J. D. Smith, following the examination of 29 members of an inbred, Arab family living within the Gaza Strip.

Kowarski syndrome describes cases of growth failure (height and bone age two standard deviations below the mean for age), despite the presence of normal or slightly high blood growth hormone by radioimmunoassay (RIA-GH) and low serum IGF1 (formerly called somatomedin), and who exhibit a significant increase in growth rate following recombinant GH therapy.

Most individuals with this condition do not survive beyond childhood. Individuals with MDS usually die in infancy and therefore do not live to the age where they can reproduce and transmit MDS to their offspring.

Naegeli–Franceschetti–Jadassohn syndrome (NFJS), also known as chromatophore nevus of Naegeli and Naegeli syndrome, is a rare autosomal dominant form of ectodermal dysplasia, characterized by reticular skin pigmentation, diminished function of the sweat glands, the absence of teeth and hyperkeratosis of the palms and soles. One of the most striking features is the absence of fingerprint lines on the fingers.

Naegeli syndrome is similar to dermatopathia pigmentosa reticularis, both of which are caused by a specific defect in the keratin 14 protein.

IP is inherited in an X-linked dominant manner. IP is lethal in most, but not all, males. A female with IP may have inherited the IKBKG mutation from either parent or have a new gene mutation. Parents may either be clinically affected or have germline mosaicism. Affected women have a 50% risk of transmitting the mutant IKBKG allele at conception; however, most affected male conceptuses miscarry. Thus, the effective ratio for liveborn children from a mother carrying the mutation is 33% unaffected females, 33% affected females, and 33% unaffected males. Genetic counseling, prenatal testing, and preimplantation genetic diagnosis is available.

In females, the cells expressing the mutated IKBKG gene due to lyonization selectively die around the time of birth so the X-inactivation is extremely skewed.

IP is caused by mutations in a gene called NEMO (NF-κB essential modulator).

Sensenbrenner syndrome (OMIM #218330) is a rare (less than 20 cases reported by 2010) multisystem disease first described in 1975. It is inherited in an autosomal recessive fashion, and a number of genes appear to be responsible. Three genes responsible have been identified: intraflagellar transport (IFT)122 (WDR10), IFT43 — a subunit of the IFT complex A machinery of primary cilia, and WDR35 (IFT121: TULP4)

It is also known as Sensenbrenner–Dorst–Owens syndrome, Levin Syndrome I and cranioectodermal dysplasia (CED)

The Jalili syndrome is caused by different mutations all with a linkage at the achromatopsia locus 2q11 on the metal transporter gene, CNNM4. Sequence analysis of this gene within Jalili syndrome sufferers has identified homozygosity or compound heterozygosity for several different mutations in the CNNM4 gene.

When originally characterized by Giedion, there was a relatively high mortality rate due to untreated kidney failure (end stage renal disease - ESRD). The remarkable improvements in kidney transplantation have reduced the mortality of Conorenal Syndrome substantially if not eliminated it entirely. Most diagnosis of the disease occurs when children present with kidney failure – usually between the ages of 10 and 14. There are no known cures for the syndrome and management of the symptoms seems to be the typical approach.

The syndrome is caused by the loss of genetic material near the end of the long arm (q) of chromosome 14 . The break that causes the telomere(s) to be lost occurs near the end of the chromosome, and is called a "constitutional ring". These rings arise spontaneously ( it is rarely inherited).Ring chromosome 14 syndrome finds itself at 14:0-107,043,718 which are the genomic coordinates.

The genetic abnormality occurs randomly in sperm or egg cells or it may occur in early embryonic growth, if it occurs during embryonic growth the ring chromosome may be present in only some of a person's cells.