Section 1, Article 3 - Compared to puberty in girls, puberty in boys looks and sounds much different. One of the first signs of puberty in boys is the growth of both testicles. By the time that boys reach the age of 12, their internal and external genitalia will experience accelerated growth. It will take approximately 3 to 4 more years for their genitalia to reach adult size. Boys experience their first ejaculation of sperm, referred to as spermarche, around age 13. Though boys can have erections as early as infancy, ejaculation indicates that sperm is being produced. Spermarche can be brought about by direct stimulation or while asleep in a “wet dream.” Other sex characteristics that develop in boys include hair growth on the face, underarms, and pubic region, which occurs at about 12 years of age. Finally, as the vocal cords and larynx continue to grow, boys’ voices begin to take on a deeper tone (; ; ).