Sex Education

Puberty (Students)

Puberty is an important stage of life. During this period, adolescents will face physiological and psychological changes which may cause some troubles for them. A good understanding of these changes and their solutions will make the transition easier.

Health Issues of Puberty

  • 1. What can I do if I have body odor?

    During puberty, large amount of sebum and sweat will be secreted in both genders. As oil and sweat accumulate on skin together with air dust, pores will be blocked, resulting in the release of an unpleasant odor. Therefore, one should pay particular attention to personal hygiene. Take shower every day at least and change underwear, outer clothing and socks frequently. Take shower whenever necessary, especially after doing sports.
    Unpleasant smell from the armpits or genital area is common in teenagers. It is hereditary and non-infectious, and will not affect health. The way to handle it is to keep good personal hygiene and change your clothes frequently. You may also consider using a deodorant or antiperspirant. Discuss with your parents and consult a doctor if the condition is serious.

  • 2. I have acne on my face, how can I handle it?

    Acne is also called pimple. Sebaceous glands secrete sebum to lubricate the skin and keep hair soft. At puberty, sebum secretion increases. When sebum traps dirt, they will block the pore and form a hard dark spot, i.e. the “blackhead”. If the follicle is infected by bacteria, it will turn red, swollen, inflamed and become a pustule. Factors such as dirty skin, greasy diet, anxiety, insufficient sleep, etc. may possibly cause your pimples to increase. Some girls have acne prior to menstruation due to changes in their hormone secretion.


    Face cleaning
    Clean your face with mild soap and lukewarm water often. This will help dilate the pores and wash away excessive oil and dirt. Pores will hence not be easily blocked and acne will be reduced.

    Healthy diet
    Drink more water and eat more vegetables and fruit to maintain a good bowel habit. Avoid eating too much oily food such as fried food, chocolate, cakes and fat meat. Smoking and drinking should be stopped.

    Healthy lifestyle
    Keep good hours and have adequate sleep. Exercise regularly and pay attention to personal hygiene especially after physical activities.

    Emotional control
    Acne may increase if there is too much emotional ups and downs. Try to stay cheerful and relaxed.

    Other issues
    Keep hands clean. Do not squeeze acne with hands or pick at the scab when the acne begins to heal. Let the scab come off naturally to avoid leaving a scar. Do not take medication without doctor’s prescription. If the condition becomes serious, inform parents and consult a doctor.

  • 3. Is masturbation harmful to health?

    Masturbation means the self-stimulation of one's own genitals with hand or other object to cause pleasurable sexual sensations. Masturbation is common in teenagers and not harmful to health. There is no need to feel ashamed of or guilty about it. However, one should pay attention to personal hygiene and do not adopt any approach that may harm your body. Do not indulge to the extent of affecting your normal social life and study. The following methods may help avoid over-indulgence:

    • Avoid getting indulged in porn books/ movies which may induce masturbation.

    • If you have any confusion or question, talk to your teachers and friends or seek advice from professionals. Avoid being alone too long and do not use masturbation as the means to escape from reality.

    • Participate in sports, join group activities and develop healthy hobbies to keep occupied so as to channel excessive energy properly.

Health Issues of Girls

  • 1. What is menstruation? What is the normal interval between two menstrual cycles?

    Most girls get their first menstruation between the age of 10 and 15. After the onset of puberty, the reproductive system under the influence of hormones release eggs periodically. At the same time, hormones stimulate the uterus to build up its lining with engorged blood vessels and this thickens the walls of the uterus. If the egg is fertilized by a sperm cell, the fertilized egg implants in the wall of the uterus and develops into a fetus.

    If the egg is not fertilized, the uterine wall stops thickening and sheds the extra tissue lining. Blood, residual cells and mucus go out of the body through the vagina, forming menstruation which lasts for 3 to 7 days.

    Irregular period for the first 2 to 3 years is common in girls who just start menstruation due to the immature reproductive system. Each menstrual cycle can be as short as 2 to 3 weeks or sometimes as long as a few months. The timing of the onset of menstruation (menarche) is influenced by factors such as genes, nutrition, climate, exercise, etc. If you have menstruation before the age of 10 or do not have menstruation after the age of 15, seek medical advice.

  • 2. How to prepare for the first menstruation?

    Nobody can predict the timing of the first menstruation. It may come suddenly but usually the bleeding is not heavy. If the first menstruation happens at school, stay calm. You can seek help from your female classmates or teachers, borrow sanitary pads from them and clean the tainted school uniform if required.

  • 3. Why do I have the menstrual cramps? How can it be relieved?

    Most teenage girls do not suffer from discomfort during menstruation, but some may have menstrual cramps. Menstrual cramps are the pain in the lower abdomen caused by uterine contractions during menstruation. They usually occur on the first or second day of menstruation but sometimes may occur even before menstruation and last for several days.

    Handling Methods:

    • Get adequate rest
    • Try to relax
    • Go to school or work as usual to divert attention
    • Use a hot water bag to ease the pain in the abdomen
    • Exercise regularly and eat and drink properly to avoid constipation
    • If the cramp gets severe, consult health care professionals. Take a painkiller under doctor’s instruction if necessary

  • 4. Is there any problem with the breast if girls find their breast swollen and painful?

    Female breasts start to develop at the onset of puberty. Breast tissues include mammary glands and fat together with some ligaments but no muscles. During this stage of development, some teenage girls find their breasts engorged and painful, and the pain will intensify if their breasts are hit by objects. This is normal. You need not worry, as long as there is no lumps in the breasts. If you find anything abnormal in your breasts, tell your parents and consult a doctor.

  • 5. Only one of my breasts starts developing. Is it normal?

    It is common for most girls to have one of the breasts developing before the other. However, if you notice the other breast does not develop long after the first, tell your parents and seek advice from a doctor.

  • 6. When should I start to wear a bra? How should I choose one?

    During puberty, breasts need support when develop to a certain degree. Wearing a suitable bra keeps the breasts supported. The bra should be chosen according to the size of the breasts. It should not be too loose or too tight. The cup should cover the whole breasts, and the straps should not be too narrow or too tight. The bra should be supportive and comfortable. It is preferable to choose a cotton bra. When you have the fitting, lift your arms up and down and turn around to see whether it fits well. If the bra is not suitable, try other size or style.

  • 7. Why do the breasts of some girls are larger while that of others are smaller?

    Many girls worry about their breast size. In fact, the size of breasts is related to genes, nutrition and amount of fat. Maintaining a healthy diet, good posture and regular exercise can enhance body growth. There is no standard breast size. Beauty exists in different sizes and shapes of breasts. So, do not worry too much about the size of breasts.

Health Issues of Boys

  • 1. Is wet dream bad to health? What is the normal frequency? When will a boy start to have wet dreams?

    When boys enter puberty, their testicles start to produce sperms in large quantities. The inhibition of our central nervous system is relaxed during sleep. The sperms will be ejected when the penis is stimulated during sleep by body turning, pressure from tight underwear/beddings or having sex dreams. This is called wet dream. Wet dreams are normal for teenage boys and are not harmful to health. Do not worry about it too much. The onset of wet dreams varies from person to person as the onset of puberty varies. Some may never experience it while others may have it once a month or up to two or three times a week. If wet dreams happen too often, you may try the following measures:

    • Sleep on your side
    • Use comfortable beddings and wear loose underwear during sleep to prevent pressure on the genitals
    • Do not drink alcohol and avoid overeating before going to bed
    • Remember to empty your bladder before sleep
    • Try not to browse porn magazines or watch porn movies

  • 2. Is it normal that the testicles are different in size and level?

    It is normal for the size and level of the two testicles to be slightly different.

  • 3. What is circumcision? Does every man need to have this operation? Will it affect growth and sexual life?

    Circumcision is the excision of the foreskin. It is not necessary for every man to have this operation. It is only indicated if the preputial opening is narrow and causes recurrent infections or affects sexual intercourse. Retractable foreskin with normal opening does not affect sexual life. Circumcision will not enhance growth.

Precocious and Delayed Puberty

Puberty takes place at a different pace among boys and girls of the same age. Puberty taking place earlier than the normal age range is called precocious puberty. While the opposite is called delayed puberty. The onset of puberty is affected by factors such as genes, nutrition, climate and exercise. Seek medical advice if you have queries.


Normal Puberty Signs of Precocious Puberty Signs of Delayed Puberty
Breast Development Between the age of 7 and 12, elevation of nipple followed by gradual enlargement of the nipple, areola and breast Breast development starts before the age of 7 Lack of breast development by the age of 13 years
Appearance of Pubic Hair Between the age 9 and 14, appearance of pubic hair follows breast development
Menarche Between the age of 10 and 15 Menarche starts before the age of 10 Absence of menarche by the age of 15 years


Normal Puberty Signs of Precocious Puberty Signs of Delayed Puberty
External Genitalia Development Between the age of 9 and 14, testicular enlargement and increase in penile size. Scrotum becomes larger with darkened skin. Development of external genitalia starts before the age of 9 Lack of testicular enlargement by the age of 14 years
Appearance of Pubic Hair Between the age 10 and 14

(Revised in June 2022)

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