The male body is very different from the female body in terms of its reproductive organs, but new advances in medical understanding of both the male and female anatomies are revealing more similarities than differences. Modern researchers are discovering that men and women have internal and external sexual parts that are of the same origin. As the embryo develops, these parts take different developmental tracks, as directed by male and female hormones, which exist in different ratios in the male and female bodies.

Pubic Mound and Pubic Bone

Men and women both have a soft, fat-padded pubic mound, which protects the pubic bone. It is covered with hair and has scent glands that distribute pheromones, sweat, and sexual stimulus scents. The hair and hair follicles add extra erotic input by stimulating the nerve endings under the skin. Gently tugging, pulling, and scratching this area can be a turn on.

The pubic bone protects the male's internal sexual parts from outside damage. In the right positions during sex, it can be effective in rubbing against the woman's clitoris for stimulation.

Scrotum

The scrotum is the sac that hangs down under the penis and contains the testes and the ductwork that allows the sperm to enter the penis and be ejaculated. The skin of the scrotum is soft, pliable, and covered sparsely with hair. Some men enjoy stimulation of the scrotum during sex.

Makeup of the Penis

The penis is comprised of several parts. On the exterior, the penile skin has an amazing capacity to expand and shrink within minutes or even seconds. As the tissue underneath fills with blood, the penis goes from flaccid to erect. Blood vessels can be seen just under the skin. These become much more prominent as the erection becomes harder.

At the tip of the penis is the foreskin. Just like the clitoral hood protects the clitoris, the foreskin covers and protects the delicate tip of the penis. If it has been removed via circumcision, the head of the penis is always exposed. The foreskin has many nerve endings and scent glands buried in it.

The penile shaft has several nerves, veins, and arteries running through it and includes the urethra, which runs through the middle. The shaft is made up of the same spongy material as the clitoral shaft — the corpus cavernosum. When this spongy material fills with blood, the penis becomes erect.

Up to one-third of the penile shaft is buried under the skin. At the other end, at the tip of the penis, is what's known as the Lowndes crown. It is buried under the tip, or head, of the penis and may be likened to the tip o f the clitoris. It is highly likely that the nerve endings here are chiefly responsible for the exquisite sensitivity of the frenulum, the membrane that connects the foreskin to the shaft and glans, close to the tip of the penis.

The glans of the penis is the very sensitive tip area. It contains a large number of nerve endings and plays a key role in male arousal. The urethra, which connects the bladder to the penis, ends here and is used for the elimination of urine; it is also used during ejaculation. Two spermatic ducts feed semen into the urethra during the ejaculation process.

At the base of the penile shaft are the two Cowper's, or bulbourethral, glands. They excrete small amounts of an alkaline fluid that neutralizes any acidity in the urine and urethral tube. This enables the sperm in the semen to travel in a favorable environment.

Prostatic Glands, or the Prostate

The prostate is actually a group of glands clustered together at the base of the penis. The duct that delivers the sperm and the two ducts that deliver the seminal fluid all convene here, so the prostate is instrumental in male ejaculation. During ejaculation, the prostate contracts and “pumps” the fluid out through the urethra.

The prostate is thought to be the equivalent of the G-spot in the woman. When directly stimulated, it is reported to add additional heightened sensuality to a man's orgasmic experience. See Chapter 15 for more on this subject.

The Testes and Sperm

The testes are two egg-shaped glands that produce sperm. They are connected to the prostate gland, where the sperm are combined with the seminal fluids to form semen, which is then ejaculated through the vas deferens, or spermatic duct. The sperm contain the genetic material that the male contributes to fertilization. Although there are many sperm in each ejaculation, it takes just one to fertilize the egg during conception.

Prior to ejaculation, the sperm is held in seminal vesicles, sacs that hold and nourish it. The sperm bathe in a solution of simple sugar and fluids that thickens the blend until it is needed in the ejaculation process.

Perineum

The perineum is a soft spot on the exterior of the body, between the anus and the base of the penis (or, in the case of women, the vagina). Although it's not always apparent that this is a sexual part, the many nerve endings that surround the anus make it very sensitive. You can experience great pleasure when the perineum is pressed firmly, perhaps because it stimulates the prostate gland in men.