Introduction: If we compare the process of conception in October to the process of a seed breaking the ground and eventually growing into a healthy seedling, the fertilized egg is the seed, the uterus is the soil on which the seed lives, and the mother’s body environment is responsible for providing the water, sunlight and air for the seed to grow. So, what role can stem cells play in this amazing process? Stem cells can help infertile men and women Human stem cells, which originally originated from embryos, are responsible for the development of the body’s organs and accompany the human body throughout its life, replenishing and repairing cells as they become depleted. Stem cells are broadly divided into embryonic stem cells and adult stem cells. Embryonic stem cells are cells isolated from early embryos and can be induced to differentiate into cells of all tissues and organs of the body, also known as totipotent stem cells. Adult stem cells, on the other hand, are commonly found in human tissues and organs: under specific conditions, they either replicate to generate new stem cells or differentiate to form new functional cells according to a certain procedure, maintaining a dynamic balance between tissue and organ growth and decline. As the role of stem cells in human reproductive system development becomes better understood, it will be possible to gradually use stem cells to treat reproductive system diseases and provide new therapies for infertility treatment. Seeds of sperm regeneration Embryos are created by the fusion of sperm and egg, and sperm is one of the members of the embryo; the seeds of sperm exist in the male testis and are called spermatogonial stem cells (SSCs). The key nutrients are provided by the testicular mesenchymal cells, and if the nutrient cells are not giving, it may lead to oligozoospermia. In this group of patients, MSCs can be transplanted to help produce sperm. For some men with severe oligozoospermia or even azoospermia, spermatogenic stem cell technology can be used to restore spermatogenic function as long as he still has heat-insensitive SSCs and supporting cells in his testes. However, if something goes wrong with the SSC itself, it can lead to azoospermia in severe cases. Currently, azoospermia patients with SSC deficiency are usually conceived through donor insemination techniques. It is also possible to transplant donor spermatogonial stem cells into the testes to produce normal sperm from the donor source and possibly even conceive naturally. Of course, it is somewhat unfortunate that a child born through these two techniques is not related to the father by blood. The process of oocyte maturation starts with a group of oocytes selected one after another from the oocyte storehouse, and they grow as they run, developing step by step into growing follicles; later more and more fall out, fewer and fewer remain, and eventually only one follicle runs to the finish line. As women age, the number of oocytes decreases, and fewer and fewer of them make it to the starting line, and the percentage of dropouts increases, so that none of them make it to the finish line. Clinically, some women’s ovaries age faster than normal, called ovarian hypofunction or premature ovarian failure, and eventually they are unable to obtain eggs, but they also want to have children of their own. However, some researchers have isolated a population of cells from the ovarian cortex of healthy women of childbearing age, which, when transplanted into the ovaries of mice, produce oocyte-like cells. Female germ cells and male germ cells are of the same origin, and there is reason to believe that at some stage of female germ cell development, or at some location in the adult ovary, OSCs are waiting to be discovered by scientists. If the existence of OSC in human ovaries is confirmed and the problem of OSC differentiation into oocyte technology is solved, women will never have to worry about menopause again. The endometrium is a fertile soil for embryos to take root. In fertile women, the endometrium regenerates over and over again with the menstrual cycle. Why is the endometrium regenerative? Because the endometrium also has stem cells! However, when the endometrium is severely damaged, the number of endometrial stem cells is insufficient and the ability to regenerate and proliferate is inhibited. In 2014, a clinical trial of “patient’s own bone marrow stem cells + biodegradable biological scaffold material” for endometrial repair and successful delivery was reported, which confirmed the effectiveness of “stem cells + scaffold” for endometrial repair. The effectiveness and safety of “stem cell + stent” for endometrial repair was confirmed. The endometrium is a piece of soil that needs the foundation and maintenance of endometrial stem cells.