What is the first sign of sexual maturation in boys?

The first sign of sexual maturation in boys is testicular enlargement. This change signals the onset of puberty and is typically followed by other physical developments associated with sexual maturation. Testicular growth indicates the body is beginning to produce testosterone and other hormones necessary for the development of male secondary sexual characteristics.

Following testicular enlargement, boys will usually experience pubic hair growth and changes in their voice, which are also indicative of puberty. Facial hair growth typically occurs later in puberty as the androgen levels increase. Thus, recognizing testicular enlargement as the initial sign helps in understanding the sequence of physical changes that occur during male maturation.