Britain’s government has voted 382 to 128 to allow “three-parent” babies through in vitro fertilisation.

The treatment, known as mitochondrial donation, takes DNA from a mother, father and female donor. It would help families with mitochondrial disease, which is incurable, fatal, and handed down through the mother’s side. Mitochondrial diseases affect one in 6,500 children worldwide.

Critics argue that this is immoral, unethical and allows scientists to play God. They say this technique could be a slippery slope toward “designer babies.”

Researchers say it’s not genetic modification because the technique doesn’t affect the DNA which determines traits and characteristics.

Mothers who carry the gene want to eradicate this death sentence.

“When you’re told that your daughter's going to die, and we really want a family, it’s really, really so hard to take, and then for them to say, ‘Oh by the way, any more children that you have would also have the disease,’ it leaves you with no hope for the future,” mother Vicky Holliday said.

Watch the report above.