This spurt occurs almost two years later in boys. Therefore boys go through a troubling period where girls are taller and heavier than them. This awkward period occurs from ages ten and one-half to thirteen. Time is not the only difference in the pubescent period for boys and girls. In girls, the enlargement of the breasts is usually the first physical sign of puberty.
Actual puberty is marked by the beginning of menstruation, or menarche.
The average age at which menstruation begins for American girls has been dropping about six months every decade, and today contrasts greatly with the average age of a century ago, which is between 15 and 17. Boys typically begin their rapid increase in growth when they reach about twelve and one-half years of age. They reach their peak slightly after 14, and slow down by age 16. The growth of pubic hair and pigmented hair on the legs, arms, and chest takes place during this period. The enlargement of the larynx, containing the vocal cords, which leads to a deepening of the voice causes much stress for a pubescent boy.