1. The older you get, the more breast fat you have. In your 20s, the breasts are made up of fat, mammary glands and collagen. As we age, the mammary glands and collagen are gradually replaced by fat. Unfortunately, large amounts of fat do not make breasts appear larger, but rather aggravate breast sagging. 2. Breast size is uncertain. Breast size varies from person to person, and the same person at different ages has very different breast sizes. The direction of the breasts is also very different, some breasts lean together, some are tilted to the sides. The average weight of a woman’s breast is 1.1 pounds (about 0.5 kilograms), accounting for 4% -5% of the body’s total fat. 3, human breasts are getting bigger and bigger. Due to nutritional and environmental factors, the female plump breast is increasingly lower. Currently, the average breast size of American women is 36D, while 15 years ago was only 34B. 4, the average female nipple side 2-15 dark hard hair. The darker the skin and hair color, the darker the color of the hair on the breast. 5. Breasts are the most tumor-prone part of the human organism. Breast cancer is the most common tumor among women worldwide. From the 1940s to the present, the incidence of breast cancer has doubled, and is still maintaining an increasing trend. 6. The skin around the breast is very thin. To keep the area of the skin moisture, you can use cream to improve elasticity, but also to prevent ultraviolet aggression, otherwise the breast is easy to grow wrinkles, nipples will also become dry. 7, the breast will also “erection”. When sexually aroused, as with the male penis erection, female breasts will also increase in size. The average length of a woman’s nipple when erect is 9.65 millimeters, equivalent to the thickness of five coins. 8. Even with a bathing suit, breasts can get sunburned. Most of the bathing suit fiber sun protection index (SPF) is only 5-7. Therefore, before swimming, breasts should be smeared SPF at least 15 sunscreen. 9, lying down to sleep the most harmful breasts. Long-term face down sleep, women’s breast tissue will be too much extrusion, leading to premature aging of the breast, skin laxity, breast deformation and expansion. The best sleeping position for breast protection is to lie on the side and put a pillow under the breast. 10, the breast monthly cycle changes. As a result of hormonal changes, menstruation has just ended for a period of time, the breast is the smoothest (this is the best time to go to the hospital for examination). Mid-term hormone levels are high, nipple sexual sensitivity is the strongest. During menstruation progesterone levels are high and breasts may be sensitive, sore or swollen. Breasts and areolas get bigger during pregnancy. 11. Protect your breasts when exercising. It is important that sports bras remain somewhat elastic to minimize damage to the breasts from exercise and reduce breast pain. Push-ups and chest expansion exercises help to exercise the pectoral muscles and make the breasts more erect. 12, breast augmentation is the number one plastic surgery. The U.S. has more than 2 million women with breast implants and at least 4 million with breast implants. The average age of breast augmentation is 34 years old, 90% of the people wait until after giving birth to children and then augmentation. This year is completed in the United States in Houston, Texas, the first case of breast silicone gel filling surgery 50 anniversary. 13, the breast lactation ability is amazing. Breast milk is rich in beneficial bacteria that can protect the intestinal tract of newborns like a vaccine. Breast milk contains 1-600 species of bacteria. Most of them are new to scientists. Breast milk contains endogenous cannabinoids, which, on the one hand, can make babies drink milk “addiction”, but on the other hand, to prevent babies from drinking too much milk.