Britain has become the first country in the world to allow the creation of babies with DNA from three different people after MPs overwhelmingly backed new legislation.
MPs voted in favour of mitochondrial donation techniques by 382 to 128 in the historic Commons vote.
Doctors say the treatment will mark a major step forward in preventing inherited diseases by allowing faulty DNA to be replaced.
But opponents argue that it could lead to so-called "designer babies" being created.
MPs have voted in favour of a ground-breaking but controversial technique that could see IVF babies conceived with DNA from three people.
A vote on three-parent babies, taking place today, could determine paediatric nurse Rachel Steel's chances of having her own healthy kids.
The parents of a baby with a life-limiting disorder say their future happiness will be decided by today's three-parent family vote.