Male and female
reproductive systems do not always function properly. On occasion, a child is born with a part of the reproductive
system malformed or missing, although the problem may not be detected immediately at birth. Girls are sometimes born without
ovaries or a uterus, and boys may have an undescended testicle. Both sexes are subject to congenital conditions involving improper amounts of hormones, affecting the proper expression of sexual characteristics. Although external defects can often be changed through surgery and hormone treatments, the person is often sterile.
Physical trauma can damage the
reproductive system: the penis and testes, located outside the body, are particularly vulnerable to damage from blows or occupational hazards from machines. Because the testes are outside the body, sperm development can be affected by external factors, such as temperature. Sperm production drops even at normal body temperature, so tight clothing or even a high fever can cause a temporary drop in sperm count, temporarily reducing fertility. Sperm count and the health of the sperm has been found to be sensitive to a man's exposure to toxic chemicals in the workplace. Infection with mumps after reaching puberty can affect sperm production and leaves some men sterile.
Women can also sustain physical damage to reproductive organs from blows to the body, as well as from accidental cutting of the uterus or ovaries during abdominal surgery or extensive internal scarring after abdominal surgery. Improperly performed abortions and improperly inserted intrauterine devices can perforate the uterus and lead to infection. Amenorrhea, the cessation of menstruation, is a symptom of a number of conditions. Hormone regulation problems, lack of ovulation, and extreme loss of weight, from anorexia or from physically demanding activities such as running or ballet dancing, can cause menstruation to stop.
Bulges in the rectum (rectocele) and bladder (cystocele) can put pressure on the nearby reproductive organs in both males and females and cause dysfunction. Prolapse of the uterus, which sometimes occurs in postmenopausal women, due to the drop in hormone levels, can cause bladder control problems. Men can get a type of varicose vein called a varicocele in the testes, which can block the pathway of the sperm, thus impairing fertility.
Bleeding at the wrong time of the menstrual cycle characterizes a number of problems in the female reproductive system. Uterine lining tissue, called endometrium, can grow on the surface of the uterus, ovaries, Fallopian tubes, bladder, or rectum, a condition called endometriosis. Like normal uterine tissue, these growths are responsive to monthly hormonal cycles, bleeding and in some cases causing great pain during menstruation. Endometrial tissue can impair fertility by covering ovaries and blocking Fallopian tubes. Another problem related to uterine tissue is fibroid tumors, in most cases nonmalignant growths in the uterus, which can cause severe menstrual cramps and bleeding between periods. Ovaries can also develop noncancerous tumors and cysts that interfere with hormone production and the normal menstrual cycle.
Sexually transmitted diseases (STDs, or venereal disease) are a significant cause of damage to the human reproductive system, especially the female system. Diseases such as syphilis, gonorrhea, chlamydia, herpes, genital warts, vaginitis (including trichmoniasis, yeast, and bacterial infections), and pelvic inflammatory disease (PID includes any number of infections of the female reproductive organs) infect both partners and can cause scarring and blockage of the narrow tubes of the reproductive system, particularly the female's Fallopian tubes, and problems such as ectopic pregnancy. Repeated infection with PID, syphilis, and other STDs can lead to infertility in women. AIDS does not directly affect fertility, but it does make the HIV-infected person more susceptible to infections, and sdies of HIV-positive women have found a pattern of increased infection of reproductive organs before diagnosis with AIDS.
Cancer can develop in male and female reproductive systems. The type of cancer and mortality rate depends on the affected organ and early diagnosis. Most treatments for cancers of the reproductive tract involve removal of the cancerous part, as well as chemotherapy or radiation. The most common reproductive cancers in women are cancer of the uterus, cervix, and ovaries. A link has been found between occurrence of cervical cancer and infection with the human papilloma virus, which causes genital warts. Cancer of the vulva, vagina, and Fallopian tubes is very rare. The most common reproductive cancers in men are prostate cancer, testicular cancer, and penile cancer. The prostate gland can cause problems even if it is not cancerous, because it tends to swell as men age, putting pressure on the urethra and causing bladder problems. Removal of an enlarged prostate gland can cause impotence in some men.