Human reproductive anatomy 101

It has become apparent that there are fully grown adults who don’t understand the facts of human reproductive anatomy. This is rather alarming. I thought everyone got the “birds and the bees” talk at home and a sex ed lesson at school, or at least figured it out on their own from interacting with people, but nope! Since this information is essential for understanding human beings, and in preventing unwanted pregnancy during intimate relationships, it’s important that everyone is aware of it.

Humans reproduce sexually, meaning we come in two sexes and we create new humans by combining a sperm from the male with an ovum (egg) from the female. Here are some helpful defintions of these terms from the American Heritage Science Dictionary (Boston : Houghton Mifflin Co., 2005).

Female: (adjective) 1. In organisms that reproduce sexually, being the gamete that is larger and less motile than the other corresponding gamete (the male gamete) of the same species. The egg cells of higher animals and plants are female gametes. 2. Possessing or being a structure that produces only female gametes. The ovaries of humans are female reproductive organs. Female flowers possess only carpels and no stamens. 3. Having the genitalia or other structures typical of a female organism. Worker ants are female but sterile. (Noun) 4. A female organism.


Male: (adjective) 1. In organisms that reproduce sexually, being the gamete that is smaller or more motile than the other corresponding gamete of the same species (the female gamete). The sperm cells of higher animals and plants are male gametes. 2. Possessing or being a structure that produces only male gametes. The testicles of humans are male reproductive organs. Male flowers possess only stamens and do not possess carpels. (Noun) 3. A male organism.

Sex: Either of two divisions, male and female, into which most sexually reproducing organisms are grouped. Sex is usually determined by anatomy, the makeup of the sex chromosomes, and the type and the amount of hormones produced. When the sex of an organism is determined by the sex chromosomes, males and females are generally produced in equal numbers. In other organisms, such as bees and wasps, in which females develop from fertilized eggs and males develop from unfertilized eggs, distribution of the sexes is unequal.

Sex chromosome: Either of a pair of chromosomes, usually called X and Y, that in combination determine the sex of an individual in many animals and in some plants. In mammals, XX results in a female and XY in a male, while the opposite is true in birds (where the designations ZW for female and ZZ for male are often used.) Sex chromosomes carry the genes that control the development of reproductive organs and secondary sex characteristics.

Sexual reproduction: The reproduction of organisms by the union of male and female reproductive cells (gametes).

Reproductive system 1. The system of organs involved with animal reproduction, especially sexual reproduction. The structure of animal reproductive systems depends on the type of fertilization (internal or external) and whether the animal lays eggs or bears live offspring. In mammals, the reproductive system consists mainly of the ovaries, fallopian tubes, uterus, and vagina in females and the testes, sperm ducts, and penis in males.

When we speak of “males” and “females” we are referring to those humans whose bodies produce male gametes or female gametes. In humans, the sex chromosomes XX produce a female (a human with female gametes) and the sex chromosomes XY produce a male (a human with male gametes). These chromosomes also produce the reproductive organs and the secondary sex characteristics. In rare cases there are people born with ambiguous sex characteristics, but this does not negate the fact that this is how human reproduction works and that most humans (at least 99%) are unambiguously male or female with typical sex characteristics.

Let’s discuss exactly what human body parts are considered male and female sex organs. From the book Anatomy and Physiology: A Complete Introduction by David Le Vay. (London : John Murray Learning, 2015.)

“The essential sex organs are the gonads, which are a pair of testes in the male forming the spermatozoa, and a pair of ovaries in the female forming the ova. The general plan of the reproductive system in both sexes is not dissimilar, but the ovaries remain in the abdominal cavity while the testes lie outside it. And in the female there is a uterus to house the developing embryo, while the penis of the male is represented in the female by the diminutive clitoris.

Male organs

The testes develop in the abdominal cavity but pass down before or just after birth to enter the loose skin pocket of the scrotum externally, where they hang down on each side of the root of the penis…The testes are ovoid, with a tough capsule made up of lobules containing the fine seminiferous tubules in which the spermatozoa are formed. Applied to their outer side is a curved organ, the epididymis, which receives sperm from the testis. It is an intricately coiled tube from which issues the ductus deferens, which is the main spermatic channel and runs up to the abdomen. Testes and epididymis lie vertically in the scrotum, surrounded by a loose serous sac.

The penis consists of a central bulb arising from the centre of the perineum, traversed by the urethra, and two lateral crura springing from the sides of the bony pubic arch. These join to form the shaft of the organ, a cross-section of which is shown in Figure 22.4 (Not included here.) Here, the part containing the urethra, the continuation of the bulb, is the corpus spongiosum below, with the corpora cavernosa, continuations of the crura above on each side. It is to these latter that the organ owes its property of increase in length and girth on sexual excitement, becoming rigid. This process of erection is due to a system of cavernous spaces which can be rapidly distended with blood from the penile arteries (p. 332).”

“Female organs

The ovaries are a pair of almond-shaped organs lying on the side-wall of the pelvis just below its brim. They are studded with the ovarian follicles, in which the egg cells or ova ripen, one coming to maturity each month. All the ova that will ever exist are already present at birth, although in a state of immaturity, whereas spermatozoa are continually formed throughout a man’s life. The ovaries are embedded in the broad ligament, which stretches from the uterus to either side of the pelvis. In the upper free edge of this ligament are the uterine tubes, or fallopian tubes, which are attached to the uterus like outstretched arms. These muscular channels open into the uterus medially and have at their outer ends a fringed, funnel-like entrance, which embraces the ovaries so as to receive the ova when shed. The uterus, or womb, is a hollow organ with thick muscular walls, lying in the pelvis between the bladder in front and the rectum behind. It communicates below with the vagina and at each side with the uterine tubes. It is tilted forwards so that its anterior surface rests on the bladder. Both surfaces and the dome or fundus are covered with peritoneum, and the peritoneal pouch between uterus and rectum is the deepest part of the abdominal cavity.

The vagina is a distensible canal, capable of receiving the penis during intercourse and of allowing passage of the child in parturition. It extends from the uterus, which it meets at an angle of 90º, to run down and forward through the pelvic floor and open externally on the perineum. Part of the cervix protrudes into the vaginal vault, the encircling rim of which is known as the fornix. The front wall of the vagina is blended with the back of the bladder and urethra. The back wall of the vagina is separated from the rectum by fibrous tissue.

The external female genitalia are known as the vulva. The includes the mons pubis, a fatty hair-covered eminence in front of the pubic symphysis. The skin folds forming the lips of the vaginal orifice comprising the outer thick labia majora and the inner slender labia minora. The clitoris is a diminutive but sensitive erectile equivalent of the penis, and lies at the meeting of the labia in front (p. 334–335).”

Fertilization is the process of making a female pregnant by introducing a sperm from the male to her ripe ovum. The fertilized egg then develops into a baby over a period of nine months. From Anatomy and Physiology: A Complete Introduction by David Le Vay:


Fusion of the male spermatozoon with the ovum normally occurs in the uterine tube as the egg is moving towards the uterus. It can only occur if a living sperm derived from the male by recent intercourse has made its way up the vagina, through the cervix and body of the uterus into the uterine tube. Success therefore depends on a near coincidence of intercourse and ovulation, approximately within 48 hours, so that the likelihood of any single sexual act resulting in pregnancy is small. When the male ejaculates, a pool of semen is deposited in the vaginal vault around the cervix. The sperm have to penetrate the cervical mucus, and upward progress is no more than 3 mm/min. their overall progress in the uterus and uterine tube is much faster, aided by muscular propulsion in these organs. During their ascent there is an enormous reduction in sperm count. Around 100 million spermatozoa are deposited in the vagina, but only a million enter the uterus, and approximately a hundred reach the ovum. Spermatozoa do not remain active and fertile in the female tract for more than two days. Once the ovum has been penetrated by a spermatozoa, rapid changes ensue. The nuclei of the two cells fuse and the ovum becomes impenetrable to other spermatozoa (p. 337).”

This is the natural process of fertilization resulting in heterosexual intercourse, but of course, due to medical science doctors can fertilize an egg in a medical clinic without the woman having intercourse.

For more relevant information on this subject, also look up menstruation, pregnancy, childbirth, and secondary sex characteristics.

There seems to be some confusion over the words “man” and “woman” and how they should be defined. The word man means an adult human male, and the word woman means an adult human female. Male and female are biological terms that refer to the gametes and structure of the reproductive organs. The word “man” is used when referring to an adult male rather than a young male. The word “woman” is used when referring to an adult female rather than a young female.

Some people use the words “man” and “woman” to refer to cultural, social and emotional ideas about who men and women are. There certainly are lots of cultural ideas about who men and women are, but that doesn’t mean that when we refer to males and females we should invoke cultural ideas, which are specific to time and place, and vary from person to person, rather than naming the reality of male and female bodies. This simply leads to confusion, since it is impossible to define “man” and “woman” coherently using cultural, social, and emotional ideas.

The idea that there are no body parts that are inherently male or female is untrue and defies the entire fields of science and medicine. If anyone wants to make a claim that what we know about human reproductive anatomy is false, they will have to provide scientific research that disproves our current knowledge.

Male and female bodies are classified as male or female based on their anatomy and genetics, not on the feelings, ideas, identities, clothing styles, or personalities of the individual.

The scientific classification of living things was not invented by feminists nor is it defined by us. It is measurable and observable information about the natural world that we can see when we study living organisms. I urge anyone who doubts this information to look it up themselves in any science textbook.


12 thoughts on “Human reproductive anatomy 101

  1. The last conversation I had with someone that was spouting nonsense about this I invited them to update the biology textbooks if it was true sex is a spectrum and all that rot. No takers there, unsurprisingly. They don’t even truly believe the trite clichés they are spouting.

    The reason why we can talk about ‘man’ and ‘woman’ in a biological as well as social and cultural context is because those social and cultural ideas are attached to our sexed bodies. This cannot be easily separated, and can’t really be discussed as if there is not a binding attachment between the two despite that social and cultural constructs of what it means to male and female shift through time and space. The careful parsing out of this as an entirely different to make it seem as if you can be a woman only in the social sense makes a false distinction between the subjective social and the objective sex categories in order to force a new meaning which includes other classes – that of male – which is ultimately untenable to attain because its an enormous porkie.


  2. Oh no, real biological science! It burns! It’s literally murdering people1

    Just kidding. I actually am a scientist (though not a biologist, but c’mon these are basic facts here) and I don’t believe in the anti-biology/denying that humans are sexually dimorphic line from the queer/trans brigade anymore than I believe in creationism or global warming/climate change denial/

    Liked by 3 people

    • I’m a biologist, been one for more decades than I like counting, and the first time I heard the drivel about sex being a continuum and not really real I just kind of stood there with a mouth full of teeth and nothing to say. A real, “Wait. Whuuuut?” moment. It took me a bit of reading and digging to realize these flamebrains meant it and were right down there with the Flat Earthers.

      The problem is that just as with Flat Earthers, there doesn’t seem to be any point discussing facts with them. They have gigaton fantasy force fields and nothing gets through.

      (No sex is not like race. Biologically, race really is a continuum.)

      Liked by 4 people

      • It’s too bad that unlike the flat-earthers, the “sex is a continuum/sexual dimorphism isn’t real” idea is being taken somewhat seriously and causing a lot of harm to lesbians and other females.
        I also avoid arguing with those people too. They won’t listen to “unapproved” ideas and frankly talking (or typing) to radical feminists and other people fed up with this is a better use of my time than wadding through rape and death threats.
        After all, things get done when you work with others like you instead of nicely asking the oppressors to knock it off.


  3. The jackwagon autogynephile who writes the horrid Assigned Male webcomic has had at least one comic where the smug MTT protagonist claims heterosexuality has nothing to do with reproduction. Even if a gay or lesbian couple has biological children, they can’t both be the birth parents! Genetic material from the other sex was necessary to create that child.

    It’s really upsetting to think of how the transactivists are trying to rewrite biological reality and declare it transphobic, particularly considering how long and hard people fought (and are still fighting, in many places) to provide young people with accurate sex ed. Feminist pioneer Mary Ware Dennett went through an obscenity trial on account of her popular, groundbreaking booklet “The Sex Side of Life: An Explanation for Young People,” and almost a century later, these transactivists share the same attitudes of the morality police who couldn’t stand the fact that young people were being provided with medically-accurate information about reproduction, anatomy, sexual relationships, and diseases. She also expressed anti-prostitution views in the closing paragraphs of her booklet (with lines like “Sex relations belong to love, and love is never a business”), so I’m sure that would make the transactivists even angrier.

    Liked by 3 people

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