Recent reports confirm the birth of eight healthy babies in the UK through three-person IVF techniques that replace mitochondrial DNA to prevent transmission of mitochondrial diseases. This process, involving mitochondrial donation and pronuclear transfer, allows embryos to inherit nuclear DNA from parents and healthy mitochondrial DNA from a donor, circumventing mutations that cause disease. Although the approach has been debated ethically and clinically, early developmental milestones appear normal in the birth cohort. These milestones were documented in studies published in The New England Journal of Medicine and underline a decade of advancement since initial mitochondrial replacement research.