(HealthDayNews) -- Some time between the ages of nine and 14, most boys' bodies begin changing as they enter their pubescent years.

The Children's Hospital of Akron, Ohio, suggests you prepare your son for changes in his size, appearance and sexuality.

Here are some of the things he'll notice:

• He'll grow taller and heavier.
• His shoulders will widen and his muscles will start to develop.
• Hair will grow in the pubic area, on his face, arms, legs, and possibly on his chest, back and lower stomach.
• His skin will get thicker and more oily.
• He'll sweat more as his sweat glands become more active.
• His voice will get deeper and may crack at times.
• His penis will grow in size and his testicles will grow and descend.
• He may feel clumsy and off-balance for a while because of the rapid growth he's experiencing.