Although the reproductive systems of men and women are anatomically different, they develop from similar embryological origins, have a similar general function of passing on genetic material from one generation to the next, and are under the control of a similar set of hormones. Reproductive dysfunction in males and females can result from a variety of causes.
Anatomy
The male reproductive system is composed of the penis, testes, ducts (for example, the epididymis, vas deferens and urethra) and the prostate, seminal vesicle and urethral glands. The female reproductive system is composed of the ovaries, fallopian tubes, uterus, cervix, vagina and glands, including Skene's and bartholin glands. The uterus is particularly well-supplied with blood vessels.
Origins
The default gonadal sex of an embryo is female. That is, in the absence of specific factors promoting "maleness" (in particular, a molecule known as testis-determining factor encoded by the Y chromosome), embryos will develop female sexual characteristics. In both males and females, the reproductive system develops in close approximation to, and in some cases, from, the urinary system.
Function
The male reproductive system is designed to produce sperm. The female reproductive system is designed to produce eggs. Sperm and eggs carry genetic information from the male and female, respectively. They normally combine in the fallopian tube of the female to produce a zygote. This zygote implants in the uterus of the female and, via a complex process of cell growth and differentiation, becomes a fetus. Because of its dense blood supply, the uterus of the female is uniquely able to facilitate, via the placenta, nutrient and waste exchange with the growing fetus.
Control
Both the male and female reproductive systems are under the control of hormones secreted by the pituitary known as follicle-stimulating hormone (FSH) and lutenizing hormone (LH). In the male, LH promotes the production of testosterone by testicular Leydig cells, while FSH promotes the overall growth of the testes. In the female, cyclical LH release promotes the production of testosterone from ovarian thecal cells, while cyclical FSH promotes the production of estrogen from testosterone by ovarian granulosa cells. FSH also promotes maturation of female eggs, while LH promotes their release from the ovary. Female menopause, which is normal female infertility that usually occurs around the age of 50, is caused by a decreasing ability of the ovary to respond to pituitary hormones.
Dysfunction
In males, reproductive dysfunction results in an inability to produce sperm, which may occur for several reasons, including infection, testosterone deficiency and genetic defects. In females, reproductive dysfunction results in an inability to produce eggs, an inability to transport eggs to the uterus, and an inability to maintain an intrauterine environment conducive to accommodating a growing fetus. There are many possible explanations for female infertility, but advanced age, abnormal uterine structure, a repeated history of sexually transmitted disease and endometriosis are common causes.
