This is such an incredible breakthrough and a huge win for science and families alike, however its sad that despite decades of work there is still no cure for mitochondrial disease. But the chance to preventing it being passed on is still such a major improvement. Also it’s sad that only the uk is capable of doing this atm bc it was the first country in the world to introduce laws to allow their creation after a vote in Parliament in 2015, while other countries were debating that it would open the doors to genetically-modified "designer" babies