The girl with three biological parents

Alana Saarinen is one of only 30 to 50 people in the world who have DNA from three different people. She was conceived through a pioneering infertility treatment in the USA which was later banned.

But soon there could be more people like Alana, with three genetic parents, because the UK is looking to legalise a new, similar technique.

The process is called mitochondrial replacement and the purpose of it is to try to eliminate debilitating genetic diseases. If Parliament votes to let this happen, the UK would become the only country in the world to allow children with three people's DNA to be born.

Rebecca Morelle reports for BBC Newsnight.