In the absence of testosterone, the genital tubercle forms the female phallus, called the clitoris. The clitoris consists of the glans and the internal organ. The clitoral glans is located just above the vaginal opening. Most of the clitoris (the body or shaft) is internal. Just below the mons pubis (that is covered with pubic hair) are the lip-like external structures of the vulva (just below the prominent bone). The labia majora (on the outside) are larger and surround the labia minora (on the inside), which are smaller. They provide protection for the clitoral glans, the urethra and the vaginal opening.
A woman’s sex organ (clitoris) is separate from her internal reproductive anatomy (ovaries, uterus and vagina). The sole function of the clitoris is to be a sex organ. Unlike a man, a woman has separate anatomy for urination (the urethra), reproduction (the vagina) and orgasm (the clitoris). These three functions are all combined for a man and provided by the penis. The female anatomy is more highly evolved (because each part of anatomy has only one function) but a man’s anatomy is more practical and convenient.
The sex organ (penis or clitoris) is the only erectile organ of the body. When a person is aroused (their mind responds positively to eroticism), the brain causes an increase in the rate of blood flowing to the genitals. Our physical arousal, which involves increased blood-flow in the corpus cavernosa causes swelling to varying degrees, called tumescence, of the sex organ (or phallus).
The clitoris is largely an internal organ. Only the tiny glans (or bud) is visible externally. The glans tends to be hidden by the labia majora and pubic hair. The glans is covered by a clitoral hood formed in part by the fusion of the upper part of the two labia minora. The body of the internal clitoral organ has two corpora cavernosa that are smaller but analogous to those of the penis. When aroused these tissues are engorged with blood. After orgasm has been achieved, the excess blood is released back into the circulation.
The clitoris is the homologue of the penis but the two organs develop very differently. The body of the clitoris consists of two parallel corpora cavernosa of erectile tissue (that measure up to 5 inches in length), smooth muscle and connective tissue (collagen and elastin) surrounded by a fibrous sheath (tunica albuginea). The clitoris doesn’t have the same mechanism that the penis has for trapping blood. The clitoris becomes tumescent (swollen) but does not become erect (rigid) like the penis. Women are largely unaware of this much lesser physical arousal. When masturbating, a responsive woman uses erotic fantasies to access her subconscious arousal.
It is very evident that men are sensitive to stimulation (capable of reaching orgasm) because of the erection they have due to blood flowing into the penis. Without this arousal, men are incapable of orgasm. The clitoris has equivalent structures (corpora cavernosa). It is inconceivable that these would not have the same function in a woman as for a man. It is equally inconceivable that women have evolved a quite different mechanism (separate from the male) for a response as basic and primitive as orgasm.
However, the clitoris is never rigid and so it lacks the sensitivity of the penis. Stimulation of the clitoral bud (even over the hood) can cause a woman to feel indifference, discomfort or even pain. If a woman stimulates her clitoral glans without any accompanying mental arousal, she feels no real pleasure. The clitoris is not an external phallus that can be used to impregnate another person. Consequently, women do not have a sex drive. Since neither the clitoris nor female orgasm are involved in reproduction, women are not aroused by the kind of real-world erotic stimuli that arouse men.
Even responsive women do not obtain the same sensational pleasure from clitoral stimulation that men enjoy from penile stimulation. Mental arousal (by focusing on surreal fantasy) and physical arousal (tumescence) provide mild pleasure. The key pleasures of female masturbation involve the pelvic contractions and the sensation of releasing sexual emotions at the end.
Female orgasm is a hangover from how the sexes evolved. Female orgasm is a miracle for two reasons. Firstly, we usually only evolve functionality for a specific (life-critical) purpose. Secondly, we also lose characteristics that have no useful function. Male orgasm triggers ejaculation but female orgasm has no role in reproduction. The clitoris is the source of female orgasm, which provides a woman’s own personal pleasure. As an internal organ, the clitoris has much less significance for a woman than the penis has for a man.
In younger women there is little discernible swelling of the clitoral organ. During periods of subconscious arousal, increased blood-flow (in mature women) can cause the internal clitoral organ to swell. If a woman places her three middle fingers over her vulva, she can feel the top of the pelvic bone. If she then runs her fingers down towards the perineum, she can feel a tingling sensation of the clitoral glans with her index finger. The swollen pubic area is noticeable both to the eye and to touch (by pressing down either side of the labia majora). Clitoral tumescence is not a sign of mental arousal nor does it help with orgasm. The main benefit of clitoral tumescence is an increased sensitivity in the pelvis during intercourse.
The clitoris, which is the phallus of the female, is the homologue of the penis of the male. (Alfred Kinsey 1953)