A biotech firm recently made news by claiming to have cloned human embryos in order to produce medically useful stem cells (SN: 12/1/01, p. 341: Human-cloning claim creates controversy). At the time, Advanced Cell Technology of Worcester, Mass., also reported trying–unsuccessfully–to derive such cells from unfertilized human eggs undergoing a process called parthenogenesis. In some animals, that process occurs when eggs begin dividing without the normal input from a sperm cell.
In the Feb. 1 Science, scientists for the company and their colleagues at several other institutions report obtaining long-lived stem cells from monkey eggs stimulated to undergo parthenogenesis.
Depending on the growth