A new study from the Harvard Stem Cell Institute shows that the incidence of breast cancer is related to when women have children, and that women who have children in their early 20s have significantly lower numbers of breast progenitor cells and are much less likely to develop breast cancer than women who have children later in life. Researchers have attempted to detect the prevalence of breast cancer by screening the number of breast progenitor cells. Breast is the symbol of every woman and a body organ that deserves our love and care, but in recent years, the dreaded breast cancer has become a nightmare that destroys women’s good life, and breast cancer is one of the most common and most frequent malignant tumors among women. Although the detection and treatment methods have been greatly improved, the complete cure of breast cancer is still a long way to go. However, a new study by scientists from the Harvard Stem Cell Institute recently found that young girls who gave birth in their early 20s had a lower chance of developing breast cancer compared to older women who married later and had children later. Researchers have also identified important markers of breast cancer and provided new insights into the diagnosis and prevention of female breast cancer. By analyzing changes in p27, an oncogene that is a marker of breast progenitor cells, scientists collected nearly 1,000 samples of female breast tissue over a 20-year period and found that women who complete a full course of childbearing in their early 20s have a lower relative number of breast progenitor cells and a reduced ability to proliferate, while women who carry the BRCA1 or Women who carry the BRCA1 or BRCA2 genes have significantly higher than average numbers of breast progenitor cells, so the researchers concluded that women who have children in their early 20s have a significantly lower chance of developing breast cancer. The results of this new study may provide additional benefits to women by screening the number of breast progenitor cells to determine the risk of breast cancer, and by simulating the effects of early childbearing to reduce the incidence of breast cancer.