In men, the breasts serve mainly to maintain the appearance of the body, while in women, they serve mainly as breastfeeding and secondary sex characteristics. Male mammary tissue begins to degenerate at the age of 1 to 2 years, and the adult male breast has only mammary ducts but almost no glandular follicles, so the glands have no secretory function and only play a role in maintaining the appearance. The female mammary glands develop under the effect of estrogen during puberty and appear hemispherical, which is the secondary sexual characteristic of females and one of the features that distinguish females from males, and has an aesthetic effect. After pregnancy, the mammary glands secrete milk under the action of prolactin and other hormones, and can breastfeed babies. Currently, breast cancer and other breast diseases are highly prevalent among women, and a small percentage of men also suffer from breast cancer and breast enlargement, etc. It is recommended that those who suffer from breast diseases consult a doctor in a timely manner.