Inhibiting p53 or Bax can be used to improve nuclease-mediated gene targeting frequencies in stem cells. This inhibition can be achieved, e.g., by overexpression of anti-apoptosis proteins or by silencing or reducing p53 or Bax expression. This technique can be used in conjunction with other rapidly developing CRISPR technologies, including improvements in specificity, other types of nucleases, and further enrichment, screening, and selection schemes, to expand the use of stem cells in experimental studies and tissue engineering for therapeutic purposes.