The testicular causes for abnormalities in sperm include
* (1) Thermal exposure
Heat potentially damages spermatogenesis or the sperm that is
stored in the epididymis. Normally the scrotal sac hangs from
the body so that its contents are actually a few degrees cooler
than the man's core body temperature.
Situations associated with increasing the scrotal temperature
include the presence of a varicocele, frequent long hot baths,
tight fitting underwear that pull the testes up to the body, undescended
testes, and sitting (especially on heated seats) for long periods
of time (such as a truck driver might do).
A varicocele is a dilatation of the pampiniform venous plexus
in the spermatic cord that is not uncommon, occurring in 10-15%
of all men regardless of fertility and in up to 25-30% of infertile
* (2) Testicular surgery
Removal of a testicle, surgical correction of undescended testes
(orchiopexy), repair of testicular torsion, treatment for cancer
of the testicle, testicular biopsy, or surgery involving the vas
deferens (vasectomy, reanastomosis of blocked portions of the
vas deferens) can all impair sperm function.
* (3) Infections
Mumps orchitis, venereal diseases, prostatitis or epididymitis
involving the testes or accessory glands (such as prostate) can
reduce testicular function. The dead sperm, infectious material
and inflammatory cells may result in an increase in a family of
molecules known as "oxygen free radicals" that might
further damage remaining sperm.
* (4) Radiation (especially involving the pelvis)
The testes are much more sensitive to radiation than the ovaries,
so that relatively low levels of radiation can result in an arrest
in sperm production. This arrest is occasionally transient with
normal production occurring months to years later. In the rat
model the time of testicular quiescence between the initial growth
of germ stem cells around birth to puberty is especially sensitive
to the effects of radiation.
* (5) Trauma
The testes and the blood supply can be damaged either during physical
activity (such as sports) or during surgery that is performed
in the vicinity of the testicular blood supply.
* (6) Substance abuse
Cigarettes, alcohol, elicit drugs (cocaine, opioid compounds,
marijuana) or anabolic steroids (for muscle building) can result
in poor quality sperm.
* (7) A general insult to the testes
High fever or viral infection can affect the sperm for up to 3
months following the event. This is because it takes months to
produce a mature sperm
* (8) Testicular cancer
Testicular cancer is associated with abnormal sperm concentration
in about 50% of men prior to chemotherapy. Following treatment
with either chemotherapy or radiation it often takes up to 5 years
for a return of function.
* (9) Medications
Chemotherapeutic agents, cimetidine, certain antibiotics (such
as erythromycin, tetracycline, nitrofurantoin, sulfasalazine),
spironolactone, and aldomet are known to compromise sperm. If
a drug interaction is suspected then switching to a comparable
alternative medication or discontinuing the medication (only if
acceptable to the prescribing physician) might result in improvement
in the sperm quality.
* (10) Toxins
Pesticides or some industrial chemicals especially if used in
conditions with poor ventilation can alter sperm quality
* (11) Chromosomal abnormalities
Factors active in early development can result in abnormal testicular
development, including the Sertoli only syndrome, congenital anorchia
(absence of the testes), Klinefelter's syndrome (XXY karyotype),
and XX males (crossover of the "testes determining factor"
onto an X chromosome)
* (12) DES exposure in utero
There is a possible association with male factor infertility according
to available research. More information about this association