What are the signs of male development?

My child is 12 years old. He has changed a lot recently. He is a boy. His voice has changed a little recently. Is it because the child has grown up? Recently, the child is unwilling to go out to play. He won't go out after finishing his homework. What's wrong with my child recently? Has he grown up? I would like to know from you about the general symptoms of boys' development.

There is no uniform classification standard for the stages of puberty, which are divided into: Early puberty: secondary sexual characteristics begin to appear and end with the first ejaculation in boys, characterized by a sudden increase in physical growth, and the age is approximately 9-13 years old.

Middle puberty: mainly focused on the development of sexual organs and secondary sexual characteristics. The first ejaculation in boys is the beginning of this period, and it ends when the secondary sexual characteristics mature. The age is about 13-16 years old. Late puberty: from the maturity of secondary sexual characteristics to the full maturity of reproductive function and the cessation of height growth, the age is about 16-18 years old.

Guidance:

At about the age of twelve, the male testicles and scrotum begin to enlarge, the scrotum turns red, and the skin texture changes. At the age of twelve to thirteen, the penis becomes longer, but the circumference increases at a slower rate. The testicles and scrotum continue to grow, pubic hair appears, and the prostate begins to become active. At the age of fourteen to fifteen, the scrotum and penis begin to continue to enlarge, the glans of the penis fully develops, the scrotum becomes darker in color, the testicles mature, and nocturnal emissions occur.

During puberty, the development sequence of boys is as follows: at 10-11 years old, the testicles and penis begin to enlarge; at 11-12 years old, the prostate begins to secrete and the Adam's knot enlarges; at 12-13 years old, the testicles enlarge, the penis grows rapidly, and the pubic hair grows; at 13-14 years old, the voice becomes deeper and nodules appear under the nipples; at 14-15 years old, armpit hair appears, the voice changes, and spermatorrhea occurs for the first time; at 15-16 years old, the scrotum becomes darker in color; at 16-17 years old, a beard grows and the pubic hair is distributed in an angular pattern; at 17-18 years old, the growth trend slows down and transitions to a mature type.

Through the detailed explanations given by the above experts, I believe you probably already know what the signs of boys' development are. When the child grows up, if the child is eleven or twelve years old, parents should observe some changes in the child, because the child may be developing during this period. Parents should not ignore the child's development period.