Learning how to reliably control the differentiation of stem cells is an important step in developing new regenerative medicine for presently untreatable injuries and age-related conditions. EurekAlert reports on new progress in obtaining neural cells from embryonic stem cells. "Scientists have long believed in the therapeutic promise of embryonic stem cells with their ability to replicate indefinitely and develop into any of the 220 different types of cells and tissues in the body. But researchers have struggled to convert blank-slate embryonic stem cells into motor neurons, says Zhang. The goal proved elusive even in simpler vertebrates such as mice, whose embryonic stem cells have been available to scientists for decades." Work is proceeding on blood stem cell differentiation too.