The earliest days after fertilization, once a sperm cell meets an egg, are shrouded in scientific mystery. The process of how ...

Scientists have found a way to study early embryonic development without real embryos. Using CRISPR, they programmed stem cells to self-organize into structures mimicking early embryos. The cells show ...

Prepubescent boys do not yet produce sperm cells. The removed tissue contains ... The procedure is part of a research project to assess whether such a transplant effectively restores fertility.

Meiosis, as described above, is the process by which certain sex cells are created. If you're male, your body uses meiosis to create sperm cells; if you're female, it uses meiosis to create egg cells.

TAF4b, a gonad-specific protein critical for mouse fertility, is not only required for long-term sperm production, but also plays a role in maintaining a population of spermatogonial stem cells, ...