AbstractA fascinating property of germ cells is their ability to maintain totipotency throughout development. At fertilization, this totipotency is unleashed and the egg generates all the cell types needed to make a brand new organism. Occasionally, germ cells differentiate precociously in the embryo or in the gonads and form teratomas, tumors containing many differentiated somatic cell types. Until recently, the genetic basis for teratoma formation was not known. The unexpected discovery of a teratoma in a C. elegans double mutant points to translational control as a key mechanism to maintain totipotency in developing germ cells. BioEssays 28: 865–867, 2006. © 2006 Wiley periodicals, Inc.