Spinal cord injury (SCI) frequently leads to long-term loss of control of bladder function and urinary incontinence. Now, researchers have partially reversed these effects in a mouse model of SCI. Human embryonic stem cells derived from the medial ganglionic eminence were transplanted into the spinal cords of injured mice. These cells were shown to differentiate into functional γ-aminobutyric-acid-containing neurons. Significant improvements in several urodynamic parameters were observed in stem-cell-injected mice, including in urine-spot diameter, intermicturition interval, voiding pressure, frequency of nonvoiding contractions and voiding efficiency relative to vehicle-treated mice.