The first clinical symptom of boys' puberty is the enlargement of male testis and pubic sac, which usually occurs around 10 years old. Then the male pubic hair comes out, and the growth and development of male pubic hair is the original song of the second sexual characteristic. Then the penis becomes bigger and wider, the human body grows taller and stronger rapidly, the beard and hair grow out and the noise becomes louder and louder. Is emotional counseling a fraud? In addition, the male prostate and seminal vesicle are enlarged, and the liquid is just metabolized, and the male sperm is slowly formed. Generally, the first nocturnal emission occurs at the age of thirteen to fifteen.
Before puberty, boys and girls of the same age have the same body shape. However, due to the different age of puberty, the starting age of growth and development is also different. Generally speaking, the growth and development peak of girls is 2 years earlier than that of boys, about 10 years old, and the growth and development peak of boys is 12 years old. Therefore, the height standard of113-year-old girls exceeds that of boys of the same age. About one year after the peak of growth and development, girls will have menstrual cramps. Once menarche occurs, the growth rate of children will obviously slow down. At the age of 14 ~ 16, the growth level of boys is higher than that of girls of the same age, and the growth rate of boys is obviously accelerated. Moreover, the growth period of boys is relatively long, so in the period of rapid growth and development, the growth and development of boys are greatly improved. In this way, by the end of adolescence, boys are obviously taller than girls of the same age. The height of girls can be increased by 5 ~ 7 cm every year, up to 9 ~10 cm; The height of boys can be increased by 7 ~ 9 cm or even 10 ~ 12 cm. According to the survey data from all over the country, the height standard for boys aged 0/7 in big cities is 168. /kloc-the height standard for girls aged 0/7 is 10cm or more. ?
Some people divide the growth and development of male reproductive organs and secondary sexual characteristics into five links. The first stage: before 10 years old, the male testis volume was only 1-3mL, and the secondary sexual characteristics were not significant. The second stage: 10- 1 1 year, the male testis and pubic canal are enlarged. The third stage: 12- 13 years old, the penis grows wider; Male pubic hair from less to more, blackened, widened and curled. The fourth stage: 14- 15 years old, the male genitalia and vaginal orifice are further enlarged, the shadow of vaginal orifice is aggravated, the glans penis is fully developed, and the male pubic hair is rhombic or shield-shaped. The fifth stage: 16- 17 years old, the appearance and size of reproductive organs are similar to those of adults, close to estrus.