Scientists have created human embryos with three parents in a development they hope could lead to effective treatments for some hereditary diseases.

Researchers from the UK's Newcastle University, presented their findings at the recent Medical Research Council Centre for Neuromuscular Diseases conference in London.
The IVF embryos were created using DNA from one man and two women.
The idea is to prevent women with faults in their mitochondrial DNA passing diseases on to their children.
Around one in 5000 children suffer from mitochondrial diseases, which can include fatal liver, heart and brain disorders, deafness, muscular problems and forms of epilepsy.