To ask the Secretary of State for Health

(1) what estimate his Department has made of the number of lives saved annually by the new in-vitro-fertilisation techniques of Maternal Spindle Transfer and Pronuclear Transfer;

(2) with reference to his Department's press release, Innovative genetic treatment to prevent mitochondrial disease, of 28 June 2013, which of the two fertilised embryos used in pronuclear transfer his Department considers saved as a result of the process.

The scientists and clinicians at Newcastle university, who have been involved in developing the mitochondrial donation techniques, initially made a conservative estimate that allowing the techniques to be used in clinical practice would enable around 10 children to be born each year free of the serious mitochondrial disease that they would otherwise have. They have recently reconsidered this and estimate it may initially now be up to 20 children per year, moving towards 80 once the techniques are established in treatment across the United Kingdom. This is based on the number of women who have mitochondrial DNA mutations of child-bearing age and the assumption that they might wish to have two children.

The purpose of these techniques is to allow a child to be born free of a serious mitochondrial disease. In the case of mitochondrial donation, the Department does not categorise one of the embryos used in the technique as having been “saved”.

The Human Fertilisation and Embryology Act 1990 (as amended) does not, however, provide for or recognise a direct correlation between those human embryos that are transferred to a woman and those that are not and, consequently, perish. It would be inappropriate, therefore, to attempt to draw a direct correlation between children born free of serious mitochondrial disease as a result of mitochondrial donation and the embryos that are created to achieve that purpose but are not transferred to the patient.