Dr. Beard and Germ Cells Dr. Beard proposed that primordial germ cells (cells destined to give rise to sperm or eggs) could migrate improperly or become “activated” inappropriately, leading to the formation of trophoblast-like cells in the wrong locations. In Beard’s view, these germ cells retained the potential to behave like trophoblasts, the highly invasive cells essential for embryonic implantation…