Molecules called endosiRNAs help us avoid genetic chaos, according to a new study from a team at the Babraham Institute. Much of the human genome contains pieces of DNA called transposons, a form of genetic parasite. When active, transposons can damage genes so it is important to keep them inactive. Early in the human life cycle controlling transposons is particularly difficult. This latest research, published today in Cell Stem Cell reveals how endosiRNAs keep our genes safe during this vulnerable stage.