Methods and compositions are provided for the treatment of medical conditions associated with a reduced rate of stem cell self-renewal or that will be responsive to an increased rate of stem cell self-renewal. Aspects of the methods include inhibiting H2A deubiquitinating enzyme activity in cells, e.g. by administering an effective amount of an H2A deubiquitinating enzyme antagonist. Also provided are screens to identify therapeutics for the treatment of medical conditions associated with a reduced rate of stem cell self-renewal or that will be responsive to an increased rate of stem cell self-renewal.