Abstract
Mitochondria are organelles responsible for oxidative phosphorylation, the main energy source for all eukaryotic cells. In oocytes and embryos, it seems that mitochondria provide sufficient energy for fecundation by supporting spindle formation during meiosis II, and for implantation. Since mitochondria are inherited from mother to child, it is important that oocyte mitochondria should be intact. Older women seem to have more mitochondrial DNA mutations, which can be responsible for poor implantation and aneuploidy, two conditions that occur more often in this group. In the present report we propose a new model to explain why older women have poor implantation rates.