Jewish campaigners have rejected claims that circumcision may be linked to an increased risk in developing autism.

A study published in the Journal of the Royal Society of Medicine showed circumcision on boys under the age of five could double the risk of them developing autism spectrum disorder (ASD), and for boys circumcised under the age of 10 the risk was raised by 46 per cent.

It also appeared to increase the risk of non-Muslims developing hyperactivity order.

The research, which was carried out in Denmark on 340,000 boys between 1994-2003, diagnosed 5000 cases of ASD among the boys who were followed until the age of nine.

Professor Morten Frisch, who led the research, believes the findings may be linked to the trauma of the pain of circumcision.

Some experts have however urged caution over what they consider to be speculative findings.

Chairman of Milah UK Professor David Katz, Professor of Immunopathology at UCL said: “This report is far from convincing: correlation does not equal causation. There is a long history of attempts to link Autistic Spectrum Disorders (ASD) to unrelated practices, such as the Measles/ Mumps / Rubella association, which proved to be fraudulent. There is general agreement that in people suffering from an ASD there are abnormalities that can be identified in brain structure and / or function. There is a strong genetic component, which may be a factor within the faith communities studied here, and which does not appear to have been explored amongst them.

Prof Katz added: “Some contemporary research does indicate that factors besides the genetic component are contributing to the increasing occurrence of ASD – for example, a variety of environmental toxins have been invoked to explain why these conditions are more prevalent today than they may have been in the past - but again proof of causation is lacking, and these factors are only likely to be relevant in those who are already vulnerable to them.”