It’s nearly a century since the Myers-Briggs Type Indicator was first conceived. It has gone on to become a multi-million pound industry categorising people from thinking introverts to feeling extroverts. But the mother-daughter team who came up with the idea had no psychological expertise and the test itself has no scientific basis, as the author Merve Emre explains to Tom Sutcliffe.

Our genes are the most important factor in shaping who we are, according to the psychologist Robert Plomin. He argues that DNA influences everything from physical traits to intelligence and personality, and that nature not only trumps nurture, but is the main driver of it too.

But the educationalist Naomi Eisenstadt argues that environment has a significant impact on children, especially in their early years. Eisenstadt was the first director of the Sure Start Unit when it was set up at the end of the 1990s and has been a government advisor on education and inequality. She questions whether there is any role for DNA testing in government policy.

Producer: Katy Hickman