3. MALE SEXUAL DEVELOPMENT
OVERVIEW
Infancy and Childhood:
Fetal Development: Sexual
differentiation begins in the
womb. The Y chromosome
triggers testes development in
males.
Birth: Baby boys have genitalia
that may still be developing.
Testes are present but not fully
matured.
4. MALE SEXUAL DEVELOPMENT
OVERVIEW
Puberty:
Onset: Generally occurs between ages 9-14.
Hormonal Changes: The hypothalamus stimulates the pituitary gland
to release hormones that trigger the testes to produce testosterone.
Physical Changes:
Growth Spurt: Rapid increase in height and weight.
Genital Development: Growth of the penis and testes.
Body Hair: Growth of pubic, facial, and body hair.
Voice Changes: Deepening of the voice due to the growth of the
larynx.
Muscle Development: Increase in muscle mass.
Acne: Due to increased oil production.
Sexual Maturation: The ability to produce sperm (spermatogenesis)
begins.
Emotional Changes: Increased interest in sex and development of
sexual identity.
5. MALE SEXUAL DEVELOPMENT
OVERVIEW
Adulthood:
Completion of Growth: Physically, most men reach their full height
by their late teens or early 20s.
Reproductive Maturity: Sperm production continues, and fertility is
established.
Stable Hormonal Levels: Testosterone levels stabilize, regulating
libido and other male characteristics.
Sexual Function: Achieving and maintaining erections, sexual
desire, and fertility are typically at their peak during early adulthood.
Aging:
Andropause: Testosterone levels gradually decline with age, leading
to potential changes in sexual function, muscle mass, and energy
levels.
Erectile Dysfunction: Becomes more common with age due to
various factors, including health conditions or medications.
7. Hypospadias
Etiology:
The exact cause of hypospadias isn't always
clear, but it's believed to involve a
combination of genetic and environmental
factors. Some factors that might contribute
include:
Genetics: There can be a familial component,
and certain genetic conditions may increase
the risk.
Hormonal factors: Disturbances in hormone
levels during fetal development, especially
androgens, might play a role.
Environmental factors: Exposure to certain
chemicals or medications during pregnancy,
such as anti-androgenic substances, may
increase the risk.
Hypospadias is a congenital
condition in males where the
opening of the urethra is located
on the underside of the penis
rather than at the tip.
8. Hypospadias
Clinical Features:
The severity of hypospadias can vary. Common
clinical features include:
Abnormal urethral opening: The urethral
opening might be along the underside of
the penis, closer to the scrotum.
Abnormal penile curvature: In severe cases,
the penis might have a downward
curvature (chordee).
Foreskin abnormalities: Sometimes associated
with an incomplete or hooded foreskin.
Potential urinary problems: Difficulty with
urination due to the positioning of the
urethral opening.
Pathogenesis:
During normal development, the urethra
typically forms as a tube running from
the bladder through the penis, and the
urethral opening forms at the tip. In
hypospadias, this process is disrupted,
leading to an incomplete closure of
the urethral groove. As a result, the
urethral opening is located anywhere
along the underside of the penis,
rather than at the tip.
9. Hypospadias
Treatment:
Treatment for hypospadias usually involves surgical
correction, typically performed during infancy or
early childhood. The specific surgical technique
depends on the severity and location of the defect.
The main goals of surgery are to reposition the
urethral opening to the tip of the penis, straighten
any penile curvature, and achieve a cosmetically
normal appearance.
10. Cryptorchidism
Cryptorchidism is a condition in which one or both testes fail to
descend into the scrotum.
Pathogenesis:
● Normally, testes develop in the abdominal area during fetal
development and usually descend into the scrotum before birth.
● Cryptorchidism occurs when this descent process is interrupted,
causing the testes to remain within the abdomen or in the
inguinal canal.
Clinical Features:
● Physical Examination: Undescended testicles can often be felt
during a physical exam, either in the groin area or the abdomen.
● Infertility: If left untreated, it can lead to infertility due to
impaired sperm production.
● Increased Risk: There's a slightly higher risk of testicular cancer
associated with cryptorchidism, especially if the condition is not
corrected.
11. Cryptorchidism
Treatment:
● Hormonal Therapy: Sometimes, hormonal treatments may be used to stimulate
testicular descent. Human chorionic gonadotropin (hCG) injections might be employed.
● Surgery (Orchiopexy): This is the primary treatment. It involves a surgical procedure
to bring the testicle(s) down into the scrotum and fixate it there.
● Timing: Surgery is often recommended before the age of one or two to prevent
potential complications and to maximize fertility potential.
Complications of Untreated Cryptorchidism:
● Infertility: Undescended testes can lead to infertility due to impaired sperm
production.
● Testicular Torsion: The testicle may twist upon itself, cutting off its blood supply,
which is a medical emergency.
● Increased Cancer Risk: There's a slightly increased risk of testicular cancer associated
with untreated cryptorchidism.
12. MICROPENIS
Clinical Features:
Clinical diagnosis of micropenis is
typically made when the penis size is
significantly smaller than the average
for a specific age group. It's often
identified at birth or during childhood.
The condition may also be associated
with other congenital abnormalities or
syndromes.
Etiology and Pathogenesis:
Micropenis is a condition characterized by
an abnormally small penis, typically with a
stretched length smaller than the average
for an age group and population. The
causes can be multifactorial, including
hormonal imbalances during fetal
development, genetic factors, certain
hormonal disorders (such as
hypogonadism or pituitary gland
abnormalities), or issues during embryonic
development affecting the genital region.
13. MICROPENIS
Treatment: Treatment options depend on the underlying cause and the individual's
specific situation. Some approaches may include:
Hormone Therapy: In cases where micropenis is due to hormonal deficiencies, hormone
replacement therapy might be considered to stimulate penile growth. Testosterone
replacement therapy can be used in certain instances.
Surgery: Surgical options might be considered in specific cases, such as when hormonal
treatments are ineffective. Surgical procedures like penile lengthening or enhancement
may be discussed, but these surgeries are often complex and not without risks. They
are typically reserved for severe cases or when there are other functional issues
associated with micropenis.
Psychological Support: Given the potential psychological impact of this condition,
counseling and psychological support can be valuable for individuals dealing with the
emotional aspects of having a micropenis.
14. Klinefelter syndrome
Klinefelter syndrome is a chromosomal disorder that typically affects males. It is
characterized by the presence of an extra X chromosome (XXY) instead of the
usual XY configuration. Here's an overview of its etiology, pathogenesis, clinical
features, and treatment:
Etiology:
The primary cause of Klinefelter syndrome is a random error in the formation of sperm
or egg cells. It occurs due to the addition of an extra X chromosome in the genetic
makeup during the formation of the reproductive cells. Advanced maternal age
might be a risk factor for this condition.
Pathogenesis:
The presence of an additional X chromosome disrupts the normal development of the
testicles, resulting in decreased testosterone production. This affects sexual
development and leads to various physical and hormonal changes associated with
the syndrome.
15. Clinical Features:
Physical Features: Individuals with Klinefelter syndrome may have taller
stature, reduced muscle mass, broader hips, gynecomastia (enlarged
breast tissue), smaller testes, and less body hair compared to other males.
Hormonal Imbalances: Reduced testosterone levels may cause delayed or
incomplete puberty, leading to infertility, decreased facial and body hair,
and a higher risk of osteoporosis.
Developmental and Behavioral Aspects: Some individuals may experience
language delays, learning disabilities, and socialization difficulties, though
these can vary widely.
Other Health Issues: Increased risk of certain health conditions like breast
cancer, autoimmune disorders, and possibly cardiovascular problems.
Treatment:
There's no cure for Klinefelter syndrome, but various treatments and therapies
can help manage the symptoms and improve quality of life
complications like osteoporosis, breast cancer, and other health issues
associated with the syndrome.
16. Androgen Insensitivity Syndrome (AIS)
Pathogenesis:
In a typical male, androgens (like testosterone)
bind to androgen receptors, initiating a
cascade of events that lead to the
development of male sexual characteristics.
In AIS, mutations in the androgen receptor gene
prevent proper binding or function of
androgens on their receptors.
Consequently, cells don't respond normally to
androgens, affecting the development of
male sexual characteristics despite the
presence of XY chromosomes.
Androgen Insensitivity Syndrome (AIS) is a
genetic condition where an individual with
XY chromosomes (typically male) has partial
or complete insensitivity to androgens, the
male sex hormones, like testosterone.
Etiology:
Genetic Mutation: AIS is primarily caused by
mutations in the androgen receptor gene
(AR) located on the X chromosome. These
mutations can lead to varying degrees of
androgen insensitivity in affected individuals.
The syndrome is inherited in an X-linked
recessive manner, meaning the gene
mutation responsible for AIS is located on
the X chromosome.
17. Androgen Insensitivity Syndrome (AIS)
Clinical Features:
Complete AIS: Individuals have external genitalia that appear female or
ambiguous. They may have a blind-ending vagina and underdeveloped or
absent internal reproductive structures (such as testes instead of ovaries).
Partial AIS: Individuals may have varying degrees of androgen insensitivity,
leading to a spectrum of features ranging from mostly male external
genitalia with some feminine features to ambiguous genitalia.
Feminization: Despite having XY chromosomes, affected individuals often have
a female gender identity due to the external appearance of female
genitalia.
Treatment:
Management varies based on the degree of androgen insensitivity:
Complete AIS: Surgical intervention might be considered to create a
more typical appearance of the external genitalia.
Hormone Replacement Therapy (HRT): Estrogen replacement therapy
might be necessary to induce puberty and maintain bone health.
Psychological Support: Given the potential impact on gender identity
and body image, counseling and support are crucial for affected
individuals and their families.
18. Congenital Adrenal Hyperplasia (CAH)
Congenital Adrenal Hyperplasia (CAH) is a group of genetic disorders
that affect the adrenal glands' ability to produce hormones, particularly
cortisol and aldosterone. The most common form of CAH is caused by a
deficiency in an enzyme called 21-hydroxylase.
Etiology:
CAH is typically inherited in an autosomal recessive manner, meaning an
individual must inherit two copies of the faulty gene (one from each
parent) to develop the condition. Mutations in genes that code for
enzymes involved in cortisol and aldosterone production cause CAH.
Pathogenesis:
The lack of functional enzymes, especially 21-hydroxylase, leads to a
decrease in cortisol and aldosterone production. Consequently, the body
produces excess androgens (male sex hormones like testosterone),
leading to various effects depending on the severity of the enzyme
deficiency.
19. Congenital Adrenal Hyperplasia (CAH)
Clinical Features:
Salt-wasting form: This severe form can be life-threatening in newborns due to a loss of salt through
the kidneys, leading to dehydration, low blood pressure, and shock.
Simple virilizing form: This form causes early development of male characteristics in both boys and
girls, such as ambiguous genitalia in females and precocious puberty in males.
Non-classical form: This form presents later in life and may cause symptoms like irregular periods,
excess body hair, acne, and fertility issues in females. In males, it can cause early appearance of pubic
hair and rapid growth.
Treatment:
The goal of treatment for CAH is to replace the deficient hormones and suppress excess androgen
production. Treatment strategies include:
Hormone replacement therapy: Cortisol replacement is crucial to replace the deficient hormone.
Mineralocorticoids may also be prescribed in some cases to regulate salt balance.
Monitoring and management of complications: Regular monitoring of hormone levels, bone health,
and addressing complications like early puberty or infertility.
Surgery: For individuals with ambiguous genitalia, surgery may be performed to reconstruct the
genitalia.
Lifelong management: Individuals with CAH often require lifelong medical management and regular
follow-ups with endocrinologists.
