Penis and Male Sexuality Facts

The Scrotum & Testicles

The scrotum or scrotal sac is a soft, muscular, thin-walled, sack containing two testicles.

male sexual anatomy

Each testicle is connected to the spermatic cord which contains blood vessels, sperm-conducting tubes and nerve and muscle fibers.

The spermatic cord is easy to feel on each side of the scrotum. Under various conditions - cold, in particular - the scrotum wrinkles up, drawing the testicles close up against the body.

Under other conditions - like relaxation or warmth - the scrotum is very loose and soft, and the testicles then hang farther from the body.

The primary function of the scrotum therefore is to serve as a natural climate control center for the testicles. The scrotum is a degree or two lower than the usual body temperature of 98.6 degrees F or 37C.

The testicles cannot produce sperm at body temperature; they need to be cooler. If kept at body temperature or higher for a prolonged period, the testicles can become infertile. The scrotum responds automatically in the way that is best for sperm production.

Men's internal sexual and reproductive organs are the testicles; the epididymis; the vas deferens; the seminal vesicles; the prostate gland; the ejaculatory ducts; Cowper's glands; the urethra.


The testicles hang in the scrotum below the penis. They produce sperm and hormones. The testicles are oval in shape, about 1-2  inches long, 1 inch wide and somewhat wider across.

An adult's testicles weigh about 28 grams each, although the left testicle is a bit heavier and larger and a little lower than the right. The reason why this should be so is not known, but it may be to stop the testicles from striking each other as the man walks.

The testicles have two functions: to produce sperm from puberty until death, and to produce male sex hormones called androgens, of which testosterone is the most important.

Hormone production from the testicles increases enormously around puberty and is high throughout adulthood until it shows a decrease after fifty or so.

Sperm are produced in structures called seminiferous tubules. These tubes are in the center of each testicle and connect with passageways that take the sperm to other important organs, such as the prostate, and ultimately out of the penis if required.

If a man does not ejaculate, he may feel a general discomfort and perhaps some tenderness in the testicles. This unpleasant feeling is called "blue balls," probably because of the bluish tint that appears when blood engorges the vessels.

The condition usually does not last long and blue balls discomfort can be exaggerated. Psychologically, men expect to ejaculate when they get an erection, and failure to have an orgasm often adds frustration and disappointment to the lesser reality of the engorged testicles' physical condition.

Some men find masturbation to be highly successful as a remedy.

Fortunately, men are beginning to see that ejaculation is not needed in every sexual situation, and that pleasure can exist without having to reach orgasm and ejaculation.

This maturity lets both men and their partners relax more, and also be more spontaneous and not feel a need to let every sexual situation end in ejaculation and orgasm.

Near the seminiferous tubules there are cells called Leydig's cells. These are responsible for producing testosterone, which is secreted into nearby blood vessels. At puberty, the changes in a boy are due to the increased testosterone in his body.

During sexual arousal, the testicles increase in size as blood vessels in the testicles engorge, causing them to increase by half as much as usual. After ejaculation they gradually return to normal size.

The testicles are drawn closer to the body just prior to ejaculation. After ejaculation the testicles move back to their usual position in the scrotum. This same drawing-up of the testicles close to the body occurs during times of intense fear, anger or when the man feels cold.

The testicles - or more accurately the scrotum - hang away from the body at the slightly lower temperature required for sperm production.

In hot weather they hang lower from the body and its warmth; conversely in cold weather the scrotum moves closer to the body's heat to maintain the right temperature.

At body temperature, testicles fail to produce sperm and a the man becomes sterile.

 When a man's muscles tense - as when he prepares for flight or aggression, or just before ejaculation - the cremaster muscles in the scrotum automatically move the testicles upwards.

Epididymis - plural epididymes

On the upper side of each testicle you can feel a ridge: the epididymis, a tightly coiled tube, which acts as a maturation and storage chamber for sperm as they move out of the seminiferous tubules. Sperm stay in the epididymes until they die and are reabsorbed by testicular tissue or are ejaculated.

Vasa Deferentia

Attached to the epididymis on both testicles is a tube called a vas deferens. Each vas deferens is about 16 to 18 inches long, and sperm slowly travel along from the epididymes into the seminal vesicles and prostate.

Because the vasa deferentia carry sperm and are easily located in the scrotum, the male sterilization procedure called vasectomy is easy: a surgeon snips both vasa, ties them, or removes a piece of tube, so stopping sperm from travelling beyond that point.

Sperm are still produced and move through the epididymes, but cannot leave the body to create a pregnancy. They break down and are reabsorbed as indeed are all the other sperm that are not ejaculated.

After a vasectomy semen continues to be produced, and leaves the body during intercourse, masturbation or wet dreams; and he subjective experience of orgasm feels exactly the same. The absence of sperm in the semen can only be seen through a microscope.

Seminal Vesicles

Just above and on each side of the prostate gland, are two pouches about three inches long that secrete seminal fluid, which mixes with sperm moved from the testicles through the epididymes and vasa deferentia and also some fluid from the prostate gland all of which accumulates in the ejaculatory duct from where the semen can move into the urethra and out of the penis.

The seminal vesicles produce a fructose solution that provides nutrition for sperm, and enables them to move optimally. The fructose in a single ejaculation has approximately 6 calories energy value!

Prostate Gland

The prostate gland is under the bladder and rests against its neck. It's the size of a large chestnut, and has a number of lobes.

The urethra runs through the prostate gland and into the penile shaft. If the prostate gland enlarges, it can press on and shut off either the bladder or the urethra, and medical attention will be needed.

From the time of puberty on, the prostate produces a fluid which aids in the nutrition of the sperm and allows sperm to move on their own.

This makes up approximately 95 percent of the semen, together with fluid from the seminal vesicles; only about one percent of semen is sperm.

Prostate fluid joins with the sperm and seminal fluid coming from the ejaculatory ducts. The semen is then ready to be ejaculated.

Most men know of the prostate gland, but they take no notice of it unless a problem occurs: this may cause a real upset in a man's life, and if surgery is required, there are two risks to the man's sexual functioning: he may suffer from erectile dysfunction or ED, or he may become sterile.

There is huge importance attached to the penis as the center of male sexuality, the symbol of manhood.

It is what makes a man a man, and it is of course the center of gratification, both for himself and for any male or female partners.

But if the penis fails to be erect, then the man is seen as only half - or less than half - a man.

This view ignores the greater part of male sexuality; but still all men feel its pressure. They also feel the pressure to perform well in bed (which seems to mean taking a woman to a screaming orgasm!)

However many men ejaculate too soon, but few understand the causes of premature ejaculation which are described here.

 Equally, few men, however relaxed and understanding, are immune to the feeling that their maleness has been reduced if they cannot become erect.

As a society, we also place great importance on the ability to father a child. Because we see that ability as an essential part of being masculine, the inability to father a child means a male is not a complete man; he lacks an essential element of maleness.

It is true that men appreciate that intimacy and loving do not need an erect penis ejaculating healthy sperm. Nonetheless, prostate surgery can cause real feelings of emasculation and impotency.

 Professional counselling is helpful and important, but the man is still likely to feel humiliated; his self-esteem mat also be reduced.

The male reproductive system
The testicles and other male organs
Functions of the testicles
All About Love Between Men and Women
How to manifest reality
All about semen
Female sexual needs and desires
Premature ejaculation
Women think about penis size and sex
Male sexual response
The significance of your erection
How do you see your penis?
Your penis and your life
Circumcision Index
Sex and your penis
Sexual psychotherapy
Sensate focus