Boys who are circumcised are almost 50 percent more likely to develop autism before the age of ten than non-circumcised boys, according to the findings of a new Danish research project.

The project – undertaken by the national serum institute Statens Serum Institut (SSI), which followed 342,877 Danish boys born between 1994 and 2003 –  showed that the risk of infantile autism, which typically affects small children under the age of five, doubles when the boys are circumcised.

”This is a robust and statistically-strong link between ritual (non-medical) circumcision and autism,” Morten Frisch, a senior investigator conducting epidemiological research at SSI, told Jyllands-Posten newspaper.

”Out research is of course not evidence as such, but the results are so convincing that researchers in other nations with a high frequency of circumcision should investigate whether they can find the same connection. This could be a bomb under the practice of circumcision.”

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Many unregistered 
According to the health authorities Sundhedsstyrelsens, about 1,000-2,000 Danish boys are ritually circumcised every year, but a small proportion are registered (just 450 last year) as many take place abroad or outside the public health system.

The vast majority of boys circumcised in Denmark have a Muslim background. The practice is also common in Jewish and American families.

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Early trauma
Frisch contended that it is possible that the early and sometimes severely painful experience could partially explain why circumcision is linked to autism.

”We know there is an increased risk of autism in children who are born in a rough way and begin their lives in the intensive wards, so perhaps a single dramatic and painful experience, as circumcision sometimes is, could have the same effect,” Frisch said.

The new SSI findings, which will be published today in the Journal of the Royal Society of Medicine, showed that 1.5 percent of all boys under the age of ten develop some form of autism.