James Turner is a geneticist working on sex chromosomes. He discovered how sex chromosome abnormalities cause infertility, and devised stem cell-based therapies to restore reproduction in these conditions. He also identified genes regulating X-chromosome inactivation, the silencing of one X chromosome that is essential for female embryo development.

Alongside his discovery science, he has been innovative in technology development. He devised the first system to produce all-male and all-female mouse litters. This approach could help reduce the unnecessary production and culling of animals of the undesired sex in research and agriculture, e.g., the egg laying industry.

James is a Principal Group Leader at the Francis Crick Institute, an EMBO member and a Fellow of the Academy of Medical Sciences.