Chinese doctor behind ‘three-parent baby’ fights regulations to help couples have babies, but at what cost?

When future historians look back on the 21st century, one of the most iconic photos may be of a smiling, dark-haired man in blue scrubs protectively holding a newborn – the world’s first commercially produced “three-parent” baby.

The man is John Zhang, the Chinese-born, British-educated founder and medical director of a Manhattan fertility centre that is radically changing the way humans reproduce.

In 2009, Zhang helped a 49-year-old patient become the world’s oldest known in-vitro mother to carry her own child. In the not-too-distant future, he says, 60-year-old women will be able to do the same.

In 2015, Zhang stunned his scientific peers by transferring a genetically “abnormal” embryo to the womb of a woman who had run out of other options. Abnormal embryos – which appear to have the wrong number of chromosomes – are almost universally considered non-viable and discarded by other fertility doctors. The woman gave birth to a healthy baby girl, prompting clinics around the world to re-evaluate their policies.

But it was the three-parent baby that really put Zhang on the map. Working with a Jordanian couple who had lost six babies – two in infancy, four through miscarriages – to Leigh syndrome, a heritable neurological disorder, Zhang put to practical use a procedure that others had dared to try only on animals.