Male sexual anatomy is mostly presented only in terms of reproduction, even though reproduction is only a fraction of what drives male sexuality. True discussions of male sexual anatomy must include the concept of pleasure, the greatest part of what drives male sexuality. A simple thought-experiment demonstrates just how great this pleasure is: Ask any adult male to calculate the number of times he has had (and will have) sex over his lifetime, then ask him to divide this number into two categories: (1) The number of times he had (and will have) sex for reproductive purposes and (2) The number of times he had (and will have) sex for purposes of pleasure. Lastly, ask him which category’s number is greater (way-way-way greater!)? Thus, this paper explores male sexual anatomy in terms of its capacities for PLEASURE and to a lesser extent, reproduction.

(Note: This paper uses the labels “male” and “female” to designate the two human organisms necessary for reproduction in nature.)

“Prominent” Male Sexual Anatomy

The most prominent part of a male’s sexual anatomy is his penis. The penis has three primary functions:

(1) Initiating orgasm.

(2) Transporting semen from the body.

(3) Transporting urine from the body.

Involving both the central and peripheral nervous systems, an orgasm is a physiological release of neuromuscular tension paired with tremendous feelings of pleasure and euphoria. More than 90% of the male population has orgasms throughout their lifetimes, and the penis, whether being physically stimulated by the male himself or some other person, is often the primary part of the male’s sexual anatomy used to initiate orgasms. For example, a 2010 study found the penis involved in two of the top three sex acts most likely leading to orgasm when males are with a partner:

#1. Receiving Anal intercourse

#2. Penile-Vaginal intercourse

#3. Receiving Penile masturbation

Having an orgasm is not the same as ejaculating. Although they often occur at about the same time, orgasming and ejaculating are in fact, two different physiological responses. Males can have an orgasm without ejaculating (dry orgasms) and ejaculate without having an orgasm (ejaculatory anhedonia). Ejaculating involves the emission of semen from the body. There is no more pleasure associated with ejaculating than there is with urinating.

Society shares more myths than truths about the length of the penis. Here are the truths. The newborn’s penis is about 1.3 inches in length. The greatest growth spurt for the penis occurs between 10 and 13 years of age. The penis typically stops growing by age 16. The average length of an adult’s flaccid (non-erect) penis is about 3.6 inches and his erect penis is about 5.2 inches. Seventy-five percent of erect penises are between 4.3 and 5.9 inches in length. Ten percent of males have erect penises less than 4.3 inches in length and 15 percent of males have erect penises greater than 5.9 inches in length.

One of the myths propagated about penis length is most females preferring a larger than average size penis during penile-vaginal intercourse. Larger than average penis size does not predict pleasure or orgasm for the male or female during sexual intercourse. The best predictors for males and females having orgasms during sexual intercourse are:

(1) Deep kissing occurring with the sexual intercourse.

(2) The sexual intercourse including oral sex, manual genital stimulation, or anal stimulation.

(3) The sexual intercourse including new sexual positions.

(4) The people involved in the sexual intercourse asking what they want.

(5) “Sexy talk” occurring with the sexual intercourse.

(6) How long the sexual intercourse lasts.

(7) Verbal expressions of love occurring with the sexual intercourse.

(8) The sexual intercourse occurring within a satisfying relationship.

If you are really interested in knowing the length of a particular male’s erect penis, then you will have to actually see it, because there are no reliable correlations between the length of a male’s erect penis and…

(1) …asking the male about the size of his erect penis.

(Surprise, surprise, males tend to exaggerate the size of their penises.)

(2) …the length of the male’s flaccid penis or the lengths of his other body parts, including his feet, hands, forearms, and overall height.

(No one body part’s size/length is predictive of the size/length of the erect penis.)

(3) …the male’s race or ethnicity.

(No one race or ethnicity is predictive of the size/length of the erect penis. Most of the “popular” myths about race being associated with penis size have deep systemic and implicitly racist roots.)

The penis has three parts (see Figure 1):

(1) Base

(2) Shaft

(3) Glans

Figure 1. The three parts of the Penis: Base, Shaft, and Glans.

Within the pelvis, and not externally visible, the base of the penis is composed of erectile tissues and muscles. Between the base and glans, the shaft of the penis is composed entirely of erectile tissue. The erectile tissue composing the base and shaft of the penis allows for erections. Erectile Dysfunction (ED) is the inability to have or maintain an erection. ED has a variety of physical (e.g., diabetes) and psychological (e.g., anxiety) causes; it affects about 1/3 of the male population. Unfortunately, only about 1/4 of men seek treatment for their ED, even though most causes of ED can be educationally, emotionally, or medically addressed.

The glans, also called the head of the penis, is highly sensitive, composed of thousands of sensory-nerve endings, and is the specific part of the penis, especially its underside, most associated with initiating orgasms. Foreskin covers the glans, except in circumcised males, whose foreskin has been surgically removed. Circumcision is controversial: It decreases the probability of acquiring the human immunodeficiency virus and sexually transmitted infections, but a 2013 study found circumcised males, when compared to uncircumcised males, had lower penile sensitivity and ability to orgasm. Lastly, the glans has the urethral opening, allowing semen and urine to exit the body.

Figure 2. The right Scrotum and Testicle.

In addition to the penis, there are two other prominent parts of the male’s sexual anatomy: the scrotum and the testicles (see Figure 2). The scrotum is a sac of wrinkled skin behind and below the penis. The scrotum contains the testicles. The wrinkly appearance of the scrotum is telling of its function. The scrotum maintains the temperature necessary for sperm production by “moving” the testicles outside of the body cavity. The temperature in the scrotum is about six degrees Fahrenheit lower than the temperature within the body. To maintain this temperature difference and normal sperm production, the scrotum moves the testicles further from the body when the internal body temperature increases, and the scrotum moves the testicles closer to the body when the internal body temperature decreases.

The testicles, also called the testes are glands that produce sperm cells, and the hormones testosterone, progesterone, and small amounts of estrogen. Testicles generally produce more testosterone than the female’s ovaries; and the ovaries generally produce more estrogen and progesterone than the testicles. However, testosterone is no longer scientifically seen as a “male hormone” and estrogen and progesterone are no longer seen as “female hormones” because all three of these hormones are needed for normal human development and sexual behavior. For example, testosterone produced naturally by the testicles or ovaries and when therapeutically given, increases sex drive for both males and females.

“Not-So-Prominent” Male Sexual Anatomy

Figure 3. The Anus relative to the Penis and Prostate Gland.

The anus is the opening at the end of the rectum through which solid waste matter leaves the body (see Figure 3). It is also a highly pleasurable sex organ for the male. As described above, a 2010 study reported when comparing males engaged in mutual masturbation, penile-vaginal intercourse, receiving anal intercourse, giving anal intercourse, receiving oral intercourse, or giving oral intercourse, those engaged in receiving anal intercourse were most likely to report having an orgasm. With its dense sensory-nerve innervation shared with the muscles involved in orgasm, few other organs besides the glans penis are as anatomically equipped to promote orgasm intensity. However, the anus does not have any self-lubricating glands to aid in anal intercourse. Thus, beyond analingus, lubricants are often necessary for pleasure to come from anal intercourse. And the best lubricants to use are store-bought lubricants because natural lubricants like saliva are associated with promoting sexually transmitted infections.

It should be noted, just as estrogen, progesterone, and testosterone cannot be typecast as specific male or female sex hormones, so too cannot anal intercourse be typecast as the “gay man’s intercourse.” Anal intercourse may involve a penis and the anus, and it is just as likely to involve a dildo and the anus. In fact, when heterosexual males are asked about their sexual behaviors, about 40% of them report having anal intercourse at some time during their lives. Comparatively, when male homosexuals are asked about their most recent sexual behaviors, about 40% report having anal intercourse. Like heterosexual males, homosexual males engage in a variety of sexual behaviors, the most frequent being masturbation, followed by romantic kissing, and oral sex. Although stereotypes and myths say otherwise, science finds no matter if we are heterosexual or homosexual, male or female, we are a lot more alike than different, when it comes to our avenues for sexual pleasure.

The internal organs composing the sexual anatomy of the male produce semen, transport sperm cells, or serve as erogenous zones. Semen is a fluid that keeps sperm cells healthy and allows for their transportation. Erogenous zones are sensitive areas of skin. When touched, males typically interpret erogenous zones as being ticklish, painful, or sexually pleasing. Erogenous zones are sexually pleasing because they increase levels of oxytocin and dopamine. Oxytocin is the so-called “love hormone,” it causes feelings of empathy, trust, love, and sensuality; and it has positive physiological effects on ejaculation and penile erections. Dopamine is the so-called “feel good neurotransmitter.” Dopamine causes feelings of pleasure and satisfaction. It also boosts attention, motivation, and mood. And because it is a significant part of the brain’s reward system, dopamine is associated with learning, memory, and emotions.

The internal organs composing the sexual anatomy of the male include the epididymis, vas deferens, seminal vesicles, prostate gland, Cowper’s glands, and urethra (see Figure 4).

(1) The epididymis is a twisted duct that matures, stores, and transports sperm cells into the vas deferens.

Figure 4. The internal organs composing the sexual anatomy of the male.

(2) The vas deferens is a muscular tube that transports mature sperm cells to the urethra, except in males who have had a vasectomy. A vasectomy involves surgically creating a void within the vas deferens. Vasectomized males ejaculate semen without sperm cells. Interestingly, a 2017 study found when compared to before having a vasectomy, vasectomized males had greater erectile function, orgasms, sexual desire, and sexual satisfaction.

(3) The seminal vesicles are glands that provide energy for sperm cells to move. This energy is in the form of sugar (fructose) and it composes about 75% of the semen. Sperm cells only compose about 1% of the semen.

Figure 5. The Prostate Gland being digitally massaged.

(4) The prostate gland provides more than 20% of the fluid composing the semen that nourishes the sperm cells. Additionally, because of its dense sensory nerve innervation, when physically stimulated, the prostate gland is associated with pleasure and orgasm. Case studies describe prostate-induced orgasms as having extreme bouts of “shaking and shuddering” and being “infinitely more pleasurable” than penile-induced orgasms (see Figure 5).

(5) The Cowper’s glands produce a fluid that lubricates the urethra and neutralizes any acidity due to urine.

(6) The urethra is a tube that carries semen and urine outside of the body.

The “Biggest” Part of Male Sexual Anatomy

Extensive regions of the brain and brainstem are activated when a male experiences pleasure and orgasm, including: the ventral tegmental area, the midbrain lateral central tegmental field, zona incerta, subparafascicular nucleus, intralaminar thalamic nuclei, lateral putamen, the claustrum, cerebellum, and Brodmann (right hemisphere) areas 7/40, 18, 21, 23, and 47 (see Figure 6). Neuroimaging studies show these regions of the brain active when males have orgasms caused by penile masturbation performed by their female partners.

Figure 6. Brain activation of Males having orgasms shown in sagittal, coronal, and horizontal perspectives.
Figure 7. Relative portions of the skin males find erogenous when alone and with a sexual partner.

As described above, the penis, anus, and prostate gland are considered primary erogenous zones bringing sexual pleasure and orgasm. Additionally, a 2013 study found males include the mouth, lips, scrotum, inner thigh, nape of neck, nipples, perineum, pubic hairline, back of neck, and ears within their “top ten” erogenous areas of their bodies. The skin is not only the male’s biggest organ, but also his biggest sex organ. In fact, a 2016 study reported males find 37% of their bodies’ skin as being erogenous (see Figure 7).


I hope this paper has removed some of the many stereotypes and myths associated with male sexual anatomy. And I hope, any knowledge you gained from this paper, allows you to recognize your sexual anatomy may be different from others, but whether you are heterosexual or homosexual or otherwise, male or female or otherwise, us humans are a lot more alike than we are different, when it comes to our avenues for sexual pleasure. Lastly, I hope this paper is merely a starting point for you to continue researching and exploring your own sexual anatomy.


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Dr. Don Lucas, Ph.D. is a Professor of Psychology and head of the Psychology Department at Northwest Vista College in San Antonio Texas. He loves psychology, teaching, and research.

If you like this story, then check out Don’s videos on his YouTube channel, 5MIweekly:, follow him on Instagram @5MIweekly, like him on Facebook:, and check out his website:

I am a Professor of Psychology at Northwest Vista College in San Antonio Texas. My research focus is human sexuality. I also host a YouTube channel, 5MIweekly.

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