The world's first three-parent baby has been born in Mexico

Fertility doctors used DNA from three different people to create baby Abrahim, who's now 5 months old.

The controversial technique allows people with rare genetic mutations to have healthy babies.

The mother has genes for Leigh syndrome, a fatal disorder that affects the developing nervous system.

Her son was conceived from an egg containing nuclear DNA from his parents, and mitochondrial DNA from a "second" mother, an unknown female donor.