The idea that race or class determines brain power has been debunked after a seven-year global study found babies can thrive regardless of their background.

The research, by the University of Oxford, used data from more than 1,000 children worldwide to try and settle the nature versus nurture debate for good. Professor Stephen Kennedy, the co-director of the Oxford Maternal and Perinatal Health Institute said: “At every single stage we’ve shown that healthy mothers have healthy babies and that healthy babies all grow at exactly the same rate.

“It doesn’t matter where you are living, it doesn’t matter what the colour of your skin is, it doesn’t matter what your race and ethnicity is. Receiving decent medical care and nutrition is the key.’ The INTERGROWTH-21st Project, which took seven years to complete, tracked nearly 60,000 mothers and babies in the womb, then followed more than 1,300 to age two. The first 24 months of a baby’s life are believed to be some of the most crucial in their brain development, with the organ reaching two-thirds of its adult weight. INTERGROWTH-21st is the world’s first study of its scope and size and produces hard-hitting evidence that how a child is raised is the biggest factor in its intelligence, researchers say. Mothers who were in good health and living in clean urban areas were selected from the UK, Italy, Kenya, India and Brazil for the final 1,300.

Results showed that as well as the speed of physical growth being approximately equal regardless of race, so was babies’ behaviour and brain development. Conditions found to affect brain development were the baby’s living conditions, the food they ate and the education they were given. The study is expected to help settle the debate over the role of genetics in determining intelligence and flies in the face of controversial assumptions about differences between races. Oxford’s Professor Kennedy said there’s still a substantial body of opinion out there in both the scientific and lay communities who genuinely believe that intelligence is predominantly determined by genes and the environment that you’re living in, and that your parents and grandparents were living in, and their nutritional and health status are not relevant. Kennedy and Jose Villar, who co-authored the project hope the data marks such a milestone and should be used by the World Health Organization alongside its baby growth charts. Although the research has not tracked children beyond their second birthdays, university attendance is one measure of intelligence for adolescents.