Developmental period if you find boys with hard lumps in the breast, the most common is the male mammary gland development, this situation occurs, most of the time is due to the child in the fetus mother, by the mother’s body of estrogen is too high, after birth to stimulate the male mammary glands gradually hyperplasia, growth, and finally the formation of hard lumps. Due to the current improvement of living conditions and standards, many boys eat food containing plant hormones or animal hormones as well as medicines, which can be acquired to promote abnormal growth within the male breast, often due to excessive estrogen in the body, resulting in excessive development of the breast, and the gradual formation of hard lumps. Therefore, the discovery of boys with hard lumps in the breast, it is best to go to the hospital for sex hormone six and breast ultrasound examination, to find the specific cause of the disease, for the cause of the systematic treatment.