This note seeks to provide a summary of the role of mitochondria, mitochondrial disease and the proposed new techniques. It will also outline the investigations into these techniques that took place prior to the Government announcement; a HFEA scientific review of the safety and efficacy of methods, an ethical review of the techniques for mitochondrial replacement undertaken by the Nuffield Council on Bioethics and an HFEA public consultation. The main safety and ethical considerations associated with the introduction of these techniques into clinical practice will be discussed.