Puberty describes the time in life when the body matures sexually and the reproductive organs begin to function. It is caused by a release of the sex hormones testosterone (in boys) and oestrogen (in girls) in the body. For girls it starts between the ages of 8-13 years, but the earliest changes occur age 10 or 11. For boys the first changes are later than the girls usually between the ages of 10-15 years, but the earliest changes occur age 11 or 12. Remember: everybody is different.




  •  firstly the genitals develop, scrotum gets bigger and darker, and testicles get larger and fuller and begin producing sperm.
  • pubic hair grows around genitals and the penis gets larger and longer, the penis starts to  ejaculate sperm, sometimes during ‘wet dreams’
  • height and weight increase during a growth spurt and facial and underarm hair starts growing, meanwhile hair on arms, legs and chest get darker and thicker
  • the body starts to sweat more causing hair and skin to become oily and spotty, the voice breaks and becomes deeper and the Adam’s apple enlarges


  • firstly the breasts and nipples get larger and nipples may darken in colour
  • pubic hair grows around the genitals, hair on arms and legs gets darker and thicker, hair begins to grow under the arms
  • hair and skin become oily and spotty as the body sweats more
  • height and weight increase during a growth spurt, hips get wider and more curvy as the fat distribution is altered
  • the vagina produces a sticky, white discharge, the ovaries begin releasing eggs and periods start


Alongside the physical changes, puberty also causes psychological changes that cause teenagers to become moody, self-conscious and aggressive and behavioural changes that cause some teenagers to experiment with new and potentially risky activities, such as smoking, drinking, alcohol and sex.



The average age to start having periods is 12. When an egg starts being released from the ovaries about every month, the lining of the womb thickens so that if the egg is fertilised it will implant and grow into a baby. If it does not meet any sperm it does not implant and the lining in the inside of the womb is shed causing bleeding from the vagina. This is a period. It can last between 3-8 days and there can be between 22-32 days between each cycle. It is normal for periods to be irregular at first. During a period, the muscular wall of the uterus contracting can cause period pains – a cramping feeling felt in the lower abdomen or back. Hormonal changes that occur a few days before a period can make girls irritable, have swollen, tender breasts and feel bloated. This is known as PMT (pre-menstrual tension, aka. PMS: pre-menstrual syndrome).