Specialists at Northwestern University near Chicago have decided that the rider Michael Martinez is not a candidate for a clinical trial using embryonic stem cells to treat spinal-cord injuries, according to the track physician at Golden Gate Fields, where Martinez was severely injured in a fall on Sept. 12. Dr. David Seftel, the physician, said that the neurosurgeons conducting the trial had concluded from Martinez’s medical records that the jockey’s spinal cord had been too severely damaged to consider Martinez for the trial. Seftel and Martinez’s family had hoped that the treatments, which have shown some promise in studies on rats, would be able to mend the rider’s severed spinal cord. Martinez is paralyzed from the waist down. The family received the news that Martinez would not be admitted to the trial on the same day that Martinez’s fiancé, Charlotte, went into labor and was admitted to Highland General Hospital, where Martinez is currently receiving treatment. The baby was expected to be delivered later on Tuesday, Seftel said. “It’s a day of extremely mixed emotions,” Seftel said. Martinez is expected to be transferred late on Wednesday to Santa Clara Valley Medical Center, which runs a rehabilitation clinic that specializes in spinal-cord injuries. Seftel and Martinez’s cousin, the rider Alex Solis, are also exploring experimental treatments with adult stem cells, though, in studies, those treatments have not shown to be as promising as the embryonic stem-cell treatments, Seftel said. “It can help with controlling some involuntary movements, like bowel and bladder control, but unfortunately, they haven’t demonstrated any significant changes in motor strength,” Seftel said. Martinez has been heavily sedated for most of the time since he suffered the injuries, but he has increasingly become more alert over the past few days. “Yesterday he ate more than I’ve ever seen a jockey eat,” Seftel said. “He’s awake, he’s alert, and he’s conversational. And, of course, he’s depressed.”