A new study published in Science Express shows that by de-activating a gene found in the X chromosome they see a 9-fold increase in cloning efficiency of the adorable mice you see above. The gene is XIST, which normally shuts down one of the two X chromosomes for females, which prevents females from having twice as many X-chromosome products in their bodies as males. However, when making clones, the gene tends to malfunction. By deleting it, the experimenters went from an average of less than one successful baby mouse clone per litter, to 3-5 successful ones.