Sex & Reproduction: An Evolutionary Viewpoint and Beyond

Arnold Mascarenhas
6 min readNov 23, 2020


Three die with the letters S, E, and X to form the word 'Sex' in red, yellow and green letters.

Try answering the following questions.

  • Do you remember a time when you felt the world was looking at you because your breasts suddenly seemed larger than before?
  • Have you ever asked your friends to check your skirt or pants for stains?
  • Did your penis start changing and you didn’t know why?
  • What about the time that your height abruptly shot up and your voice changed?
  • Did your face suddenly start sprouting pimples and acne?
  • What about the growth of pubic and body hair?

We have all experienced unusual changes in our bodies that very few of us were ready for beforehand. This scary time most likely happened anywhere from the ages of 10–16, depending on your sex and where you grew up.

Our bodies go through major changes during adolescence and continue to change throughout our lives. What are these changes that we go through? Why do we have the organs that we do?

All of these questions have their own independent explanations, and it’s a vast subject that can not be covered in a single article. But we would like to make a start with the basics to help explain and clarify.

Reproduction without sexual organs for human beings: Not possible

All this drama for reproduction; seriously?

So yes, human bodies undergo all these subtle and not-so-subtle changes to prepare for reproduction.

Any part of a person’s or animal’s body that is involved in the process of reproduction is called a sexual organ.

That includes the penis and the vagina (actually vulva; but more on that later). However, are these the only organs important for sex, or are there more?

The female reproductive system includes:

  • the ovaries,
  • fallopian tubes,
  • uterus,
  • vagina,
  • vulva,
  • mammary glands,
  • breasts

While the male reproductive system includes:

  • the penis,
  • scrotum,
  • testes,
  • epididymis,
  • vas deferens,
  • prostate,
  • seminal vesicles
Human Reproductive System Illustration Diagram, Male and Female. Medicine educational information.

(Even we had to re-learn about some of them to write this article!) We expand on them (and on puberty) in greater detail in our subsequent articles.

Reproduction is nature’s grand game that involves attracting a mate, being guided by hormones, and nourishing the foetus (unborn baby).

Is sex the ‘only’ way to reproduce?

If we look at the history of evolution before sexual reproduction, organisms reproduced asexually. That means without coming together and having sex. They reproduced by cell division. Remember studying about the amoeba in school?

illustration of biology, All organisms copy their DNA when cells divide, replication of the entire organism's body is also a simple matter of copying, Asexual reproduction diagram

Asexual reproduction saved the organism the effort to impress a mate.

But over time with evolution this changed and organisms grew more sophisticated. Bodies began to possess unique systems for different functions. Initially, a single cell could nourish itself, reproduce, and clean itself independently. Then we had different cells coming together to perform specific functions. Thus, we ended up with different systems to think, to digest, and to reproduce.

With organisms becoming more complex, many organisms had to search for a partner to procreate with. And in the course of sexual reproduction, the need to attract a mate developed.

Mating pair of fishes: regular Jack Dempsey female and Electric Blue Jack Dempsey male from Central America in the aquarium
A huge number of species play the attraction and seduction game

Flirting is not restricted to humans only

The peacock flaunts its vibrant feathers to attract the peahen. The bird of paradise dances to attract his mate. The male pufferfish draws patterns in sand of a diameter of around 2m. If the female is happy with the creation, she agrees to mate.

Peacock courting ritual, peahen looks at male. Reproduction takes place after attraction between the partners.
A peacock trying to impress a potential mate, a peahen

Humans also have to attract mates for reproduction and prove that they can provide for their offspring. From an evolutionary standpoint, there are various characteristics that trigger a sense of attraction between partners.

Similar to animals, physical traits like appearing symmetric, tall, broad, muscular, possessing rounded hips and breasts are typically associated with being fertile and hence found attractive. Studies indicate that these are signs of protection, youthfulness, and nutrition for the potential offspring.

According to scientists, these instincts still play a predominant role in how we respond. However, our complex development has enabled us to notice not just physical traits. We also experience attraction at an emotional and mental level. This is usually why we are attracted towards someone who we think is smart, funny, kind, and thoughtful. These traits (besides just the physical ones) help us feel safe and comfortable expecting that they will be valuable partners and good parents to our children.

It’s important and interesting that our preferences are shaped by the society we live in and can vary from one culture to another. And these preferences change over time even within a particular culture or society.

Back of a couple showing as one of the partners is pointing at something.
The complex evolution of humans has enabled us to notice not only the physical traits of potential partners, but emotional and mental aspects too

But is reproduction the only aim of sex?

From an evolutionary point of view, reproduction ensures that a species does not become extinct. We have sex and reproduce so that homo sapiens continue to exist on the planet.

However, research indicates that the aim of having sex is NOT just to procreate. Various species have sex for reasons other than reproduction.

The human instinct or urge is to have sex, is not just to make babies. Saying that sex is the urge to procreate is similar to saying that we eat to defecate.

As far as humans go, some of the other reasons we have solo sex (masturbation) or partnered sex include:

  • pleasure,
  • stress relief,
  • physical desire,
  • thrill and desire for new experiences,
  • emotional reasons including love (and a way to express love), and
  • boosting our self-esteem
Woman holding a bedspread with her hand to indicate pleasure. Sex is more than reproduction.
Physical pleasure is a huge reason humans indulge in sex

To conclude

There are many reasons for people to have sex besides making babies. Besides pleasure, people also have sex as an emotional response in an intimate relationship. Sometimes people have sex purely out of curiosity. Many have sex to make money, and there are regions where it is legal and regulated. If sex was all about reproduction, Durex, Kama Sutra and all the other condom or sexual wellness companies would not be operating. Furthermore, sex doesn’t always involve penetration.

Sex is a natural human desire (more on ‘asexuality’ later). Whether to wait until marriage or not, or whether to have sex to procreate or for pleasure are all very personal choices.

The important thing is to accept that people approach sex in many different ways and that there is no single, right approach. We all have our own paths, and making the right choices based on self-awareness and respect for others is critical to our wellbeing.



Arnold Mascarenhas

Lokyatha is an education focused initiative to enable young adults to live better, more fruitful lives by delivering real world life skills.