While it’s common knowledge that all organisms inherit their mitochondria — the cell’s “power plants” — from their mothers, it hasn’t been clear what happens to all the father’s mitochondria. Surprisingly, how — and why — paternal mitochondria are prevented from getting passed on to their offspring after fertilization is still shrouded in mystery; the only thing that’s certain is that there must be a compelling reason, seeing as this phenomenon has been conserved throughout evolution. A crucial step in fertilization, and this issue, is now better understood, thanks to recent research.