Stanford University is reporting that they have injected the fourth patient with embryonic stem cell-derived cells in Geron's experiment on patients with a specific type of spinal cord injury.

Geron had previously announced the first and second patients, but not the third patient who was apparently injected in the last couple of months in Atlanta. Up to ten patients may be tested in the initial experiments. Patients will be monitored for 15 years because of the significant risk of tumor development. Scientists are still trying to overcome the cancerous potential of embryonic stem cells.

Adult stem cells have already successfully improved dozens of spinal cord injury patients, documented by peer-reviewed publications, and all without concerns for tumors, transplant rejection, or harm or destruction of the stem cell donor.