HEALTH

* Geron Corp. shares fell for the second day, after skyrocketing last week, as investors realized that the biotechnology firm’s new research on cells isn’t likely to translate into a lucrative product soon. Shares of the Menlo Park-based company fell $1.50 to close at $12.25 on Nasdaq. Geron rose 74% last week on news that the company had managed to isolate in the laboratory a human embryonic “stem cell” that can develop into any kind of human cell.