What happens to boys?

The following changes start to show in boys around 11 or 12:

• shoulders broaden
• muscle mass increases
• their voice becomes husky and ‘breaks’ a year later to take on deeper tones
• pubic hair and underarm hair appears (more active sweat glands in boys result in a distinct perspiration odour – this is normal)
• upper lip and chin hairs appear (sometimes funny to the family, but rarely to the boy)
• genitals grow
• first ejaculation (as startling an experience as a girl’s first period but usually discussed less).
  

Changing hormones can lead to enlarged breasts in boys. Called gynaecomastia, it’s usually mild and may affect up to 80 percent of boys.