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11.3. Adolescence and sexuality

Adolescence and sexuality

The puberty is the first phase of adolescence, when the activity begins the reproductive organs and remarkable physical and psychological changes occur in adolescents who just stop being children.

Humans present sexual dimorphism, since men and women have different physical and psychic characteristics that differentiate them.

The determination of sex in humans is chromosomal. Of the 46 chromosomes that we have, a pair is the sex chromosomes. In the case of women, there are two chromosomes called XX while men have an X chromosome and a different smaller one called Y, with genes responsible for male differentiation. In Biology and Geology of 4th ESO we will see how the inheritance of sex occurs.  

Very interesting article (from Determination of sex in humans: more than XX and XY.

The differences between men and women

The sexual characteristics are the differences between men and women. They are due to the action of different hormones that have been acting throughout people's lives. We can distinguish two types of sexual characters:

Primary sexual characters

The primary sexual characteristics are those that we have from our birth. The sexual organs, determined from the moment of fertilization, is the only thing that allows us to distinguish between young boys and girls.

Later, the gonads, when they mature, in addition to producing sex cells, will produce hormones that will cause the appearance of secondary sexual characteristics.

Secondary sexual characters

The secondary sexual characteristics are important bodily changes that occur in puberty. These characters are not directly related to reproduction but are different in males and females:

  • Secondary sexual characteristics of the woman:
    • Puberty usually arrives between the ages of 10 and 14, with the production of estrogens and progesterone.
    • They are usually shorter than men.
    • The breasts develop.
    • Greater accumulation of fat in the hips and thighs.
    • Wider hips and fat accumulation.
    • Hair grows in the pubis and armpits.
    • Higher voice.
    • Vaginal discharge occurs.
  • Secondary sexual characteristics of the man:
    • Puberty usually arrives between the ages of 12 and 15 due to the action of the hormone testosterone.
    • They are usually taller and heavier than women.
    • Greater development of the muscles.
    • Wider shoulders and chest.
    • They have more hair on their bodies and faces. They have a beard and mustache.
    • Deeper voice due to a wider larynx.
    • The apple appears (laryngeal protrusion or Adam's apple).
    • Nocturnal pollutions appear (involuntary ejaculations when they are asleep).

Caracteres sexuales secundarios

By Libni14 (Own work) [CC BY-SA 4.0], via Wikimedia Commons

Activity: Secondary sexual characters.

Curiosity: Symbol of the male and female sex

The male is represented by the symbol . It corresponds to the symbol of Mars, a Roman god represented by a shield and a spear oriented towards the upper right side. It seems that this symbol is used because the man had to go hunting to get food to take back to his family.

The female sex is represented by the symbol ♀, which corresponds to the symbol of Venus. A circle with a cross at the bottom represents the goddess Venus with a hand mirror. It seems that this symbol is used because while the man went hunting, the woman stayed at home getting ready.

What do you think that these symbols are still used today?

There are also other theories that say the symbols come from contracciones en la escritura griega de los nombres griegos de los planetas Thouros (Marte) y Phosphoros (Venus).

Linnaeus was the first to use these signs in a biological context in his work Plantae hybridae (1751), where he used the symbol of Venus to designate a female parent and the symbol of Mars to designate a male parent of a plant.

CC0 Public Domain. Tomada de 

Adolescent behavior

The adolescence is the period of human life ranging between puberty, which would mark the end of childhood, and age adult. Although the adolescent continues to depend on his parents, he already acquires the knowledge and skills necessary to live in society as an adult .

As a guide, adolescence can be divided into three stages, each with its own characteristics:

  • Early adolescence: between 12 and 13 years of age.
  • Middle adolescence: between 14 and 16 years old.
  • Late adolescence: from the age of 17.

In these years, in addition to acquiring physical and sexual development, he also matures psychologically, acquiring an intellectualsocial and emotional maturity that will lead him to be an adult. In this stage of change, the adolescent perceives that he is treated as a child for some things but adult responsibilities are demanded of him for others. Although not all people go through adolescence in the same way, it is normal for:

  • They feel uncomfortable with their new look and try to differentiate themselves from others.
  • Try to be more independent by staying away from your parents.
  • Question the decisions that the adults in your environment make, so their behavior can be rebellious.
  • They feel the need for support from the group of friends, with whom they are looking for signs of identity (clothes, music, etc.).
  • Have the first romantic relationships.
  • Go from having a group of friends of the same sex to a mixed one.
  • Have a need for new sensations and experiences .

Grupo de adolescentes sentados junto al Río Ebro (Zaragoza)

Activity: True or false.

Answer in your notebook

11.11.- Is reproduction the same as sexuality? Reason for the answer.

Answer in your notebook

11.12.- What does it depend on whether a couple's child is a boy or a girl?

Contesta en tu cuaderno

11.13.- Think of a 1st or 2nd ESO class. Why are girls usually taller than boys?

Recommended documentary: Adolescence, the hormonal rebellion. It is a long video, 49 minutes, and we cannot see it in class but I recommend that you watch it so that you can see the changes that occur in adolescence.

Sexual health

Positive aspects

The sexuality is the set of emotional phenomena, behavior and practices associated with the pursuit of sexual pleasure, marking decisively to the human being in each and every one of the decisive phases of their development.

Sexuality encompasses biologicalpsychologicalsocial and ethical aspects, which are part of how we perceive things related to sexuality. Sexuality encompasses sex, the identities and roles of gender, the eroticism, the pleasure, the intimacy, the reproduction and sexual orientation. It is lived and expressed through thoughts, fantasies, desires, beliefs, attitudes, values, behaviors, practices, roles, and interpersonal relationships.

Although before birth we have a sex and gender assigned, the sexuality of each person's identity may be different. There may be people who do not feel the biological sex that determines their genitals and who opt for hormonal or surgical treatment to change them (transsexuals). Also, people can be attracted to other people who can be of the opposite sex (heterosexual), of the same sex (homosexualgay or lesbian) or to people of both sexes (bisexual).

The sexuality, although they live differently along the different stages of life, is part of everyone's life.

The sexual relationship begins when two people are physically attracted and a set of complex physical and emotional reactions take place, where feelings, affection, etc., are mediated by hormones responsible for the sensations of pleasure of the general well-being of the organism.

The sexual relationship tries to seek pleasant sensations, but they always have to be based on respect and responsibility, without any type of coercion, discrimination or violence.

Highly recommended documentary about transsexuality in children: The felt sex.

Negative aspects

Although human sexuality is part of the person and has many positive aspects, it can sometimes lead to negative situations, such as  unwanted pregnancy and sexual abuse.

Teenage pregnancy

Although there is increasing information and access to contraceptives, teenage pregnancy is a current problem. Adolescents have the personal choice of having sex, but they have to do it in a responsible way, since they have to take into account that:

  • They do not have the emotional maturity of an adult.
  • If they are still dependent on their parents, they are not independent in order to raise a child.
  • The educational formation of the mother and father is altered.
  • Family and social relationships change.

Sexual abuse and gender violence

The gender - based violence is a form of physical or psychological violence against any person because of their gender. Too often, this physical violence occurs in the privacy of the home, although psychological abuse also occurs. But sadly, this violence also occurs between teenage couples.

In addition to gender-based violence, sexual abuse can also seriously harm the victim, both physically and emotionally, even more so if they are adolescents due to their immaturity.

It is necessary to take into account that:

  • Abuse is not only physical violence, but insults, threats and harassment are also signs of abuse.
  • Abuse usually occurs from a stronger person to a weaker person.
  • It generates psychological disorders that are difficult to overcome.
  • It is necessary to report any situation of abuse, not feel guilty and not keep it a secret, trusting family, friends and teachers.

We also have to talk about grooming, when an adult tries to gain the child's trust, with gifts, paying attention, etc. to be able to abuse them sexually. It can occur in any type of places that the child frequents, but you have to be especially careful on the internet, because an adult can impersonate a minor, get some kind of compromised photo and blackmail the child to ask for even more compromised photos and even encounters sexual.

Web: Sexpresan. Multimedia for affective-sexual education.


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Biology and Geology teaching materials for Compulsory Secondary Education (ESO) and Baccalaureate students.