It's not the first time scientists have created babies that have DNA from three people - that breakthrough began in the late 1990s - but it is an entirely new and significant method. [...] The US team, who travelled to Mexico to carry out the procedure because there are no laws there that prohibit it, used a method that takes all the vital DNA from the mother's egg plus healthy mitochondria from a donor egg to create a healthy new egg that can be fertilised with the father's sperm.

[...] Some have questioned whether we are only now hearing the success story while failed attempts could have gone unreported. Prof Alison Murdoch, part of the team at Newcastle University that has been at the forefront of three person IVF work in the UK, said: "The translation of mitochondrial donation to a clinical procedure is not a race but a goal to be achieved with caution to ensure both safety and reproducibility." Critics say the work is irresponsible. Dr David King from the pro-choice group Human Genetics Alert, said: "It is outrageous that they simply ignored the cautious approach of US regulators and went to Mexico, because they think they know better. Since when is a simplistic "to save lives is the ethical thing to do" a balanced medical ethics approach, especially when no lives were being saved?" Dr Zhang and his team say they will answer these questions when they presents[sic] their findings at a meeting of the American Society for Reproductive Medicine in October.