A new study that combines data from more than 20 million births has found that a caesarean section delivery is associated with autism spectrum disorder and attention-deficit hyperactivity disorder.

However, the study does not indicate that caesarean section deliveries cause autism or ADHD. The truth is much more difficult to decipher, and provides an excellent case study for the old adage that correlation doesn’t equal causation.

Autism and ADHD are neurodevelopmental disorders with clear differences in behavioural development that we presume are due to brain differences.

In the case of autism, behavioural differences occur in the part of the brain primarily responsible for social and communication development.