The circumcision of boys is controversial and hotly debated in many countries.
Advocates of circumcision point to cultural, religious, hygiene-related and medical reasons for the procedure, while opponents argue that it infringes on bodily rights and is a severe, painful assault on the individual which can lead to life-long physical and mental damage, with no relevant advantages to health.
A study now pours a little more oil on the flames.
According to the new study, which included 340,000 Danish boys, it looks as though circumcision increases the risk of developing autism.
It shows that there are twice as many Danish boys under age five with infantile autism among those circumcised compared to those who were not.
The study was conducted by Morten Frisch, consultant and senior investigator in epidemiological research at Statens Serum Institut and adjunct professor of sexual health epidemiology at Aalborg University, in collaboration with statistician Jacob Simonsen.
The study has been published in the Journal of the Royal Society of Medicine.
In the study, the scientists examined Danish health records and data for all Danish boys born between 1994 and 2003, a total of 340,000 boys.
In the analysis they discovered the link between the boys which had developed autism and those which had been circumcised.
They found that circumcised boys under five years of age face twice the risk of developing serious infantile autism compared boys who had not been circumcised.
The reason for the correolation between circumcision and autism is not clear. The study only points out that there is a connection.
According to Professor Frisch the association, if it can be confirmed by other studies, may be due to the intense pain some boys experience during circumcision.
The circumcision of a small boy is a severe intervention, in which the foreskin is first pulled free of the head of the penis, then cut off. Frisch explains that if the only anaesthesia applied is local, in the form of some EMLA magic cream, the pain will undoubtedly be intense.
"We don't have an explanation, but the small child's pain could be significant to the later development of autism," says Frisch.
According to Frisch, the study's findings give rise to a broader question regarding the significance of painful experiences:
"Other scientists have found that premature babies who start life in an intensive care unit and are subjected to a large number of painful examinations exhibit changes in pain behaviour later in childhood, which is often seen in children with autism. Our results call for more detailed examination of the possible significance of the children's autism risk when they are subjected to painful, traumatic experiences in their earliest childhood," says Frisch.
Professor Carsten Obel from the Department of Public Health, Aarhus University, researches mental illness in children.
Of the 340,000 included in the new Danish study, 5,000 developed autism spectrum disorders, while 800 developed infantile autism.
The Danish National Association for Autism is extremely sceptical of the new findings. Scroll down to read their reaction to the study.
Obel agrees that the study appears to show a slight excess frequency of autism among circumcised boys.
He does, however, believe it is going a bit too far to conclude that autism should be caused by the pain caused by circumcision.
"The burning question is wether there is a causal relationship. In my opinion, there could easily be some other explanations for the connection found by the study," says Obel.
The professor points out that people who have their baby boys circumcised may differ from those who do not, and that these differences could relate to a predisposition to autism.
"Now that the suspicion has been raised we need to get to the bottom of it and determine for sure whether or not circumcision can be related to autism," says Obel.
The Danish National Association for Autism: linking autism and circumcision is highly misleading.
The Danish National Association for Autism is extremely critical of the study's findings and urges that international projects further investigate the area before any conclusions are drawn.
"Autism is one area of neurology where we are really short of answers. This is why we, unfortunately, come across professionals who believe they have found the mystery of autism by linking it to their own special interest in another area of research in order to attract attention. It is obvious that this new study was conducted by scientists who are not specialists in autism," writes the chair of the Danish National Association for Autism, Heidi Thamestrup, in a press release.