The signs of sexual development during puberty include height growth and the development of primary and secondary sexual characteristics. 1. Height growth: Generally speaking, when a boy enters puberty, his height will increase by about 9 to 11 centimeters every year, but of course, there is a big difference between individuals, and it is also necessary to take into account his own physical condition, genetics, nutrition and other factors. 2. Development of secondary sexual characteristics: the first manifestation of the scrotum and testicles increase in size, the scrotum skin texture, began to turn red; then the penis began to grow, at first mainly growth, and subsequently, the circumference has also increased, and gradually deepen the color of the scrotum and penis, and finally, the size of the genitals tends to be close to the level of normal adults. 3. Development of the first sexual sign: the development of the first sexual sign is mainly marked by seminal emission. During puberty, males need to consume comprehensive and balanced nutrition, and at the same time with sports can promote height growth, and should also maintain mental health.