However, symmetrically dividing bacteria and yeast can be biologically immortal under ideal growing conditions.[12] In these conditions, when a cell splits symmetrically to produce two daughter cells, the process of cell division can restore the cell to a youthful state. However, if the parent asymmetrically buds off a daughter only the daughter is reset to the youthful state - the parent isn't restored and will go on to age and die. In a similar manner stem cells and gametes can be regarded as "immortal".