If the sun is out today, will you be enjoying it? Do you yearn for the first spring rays that warm the skin and lift the spirits? As summer approaches, will you be taking off your clothes to worship the sun?

If so, spare a thought for one Michael Holick, Professor of Dermatology at Boston University in America, who was recently sacked for suggesting that the sun might actually do us some good.

Professor Holick's crime was to publish a book, out this month in the US, called The UV Advantage, which charts the benefits that come from ultraviolet light. His contention is that the benefits of the sun as a key source of vitamin D (through its action on the skin) outweigh the risks of skin cancer and premature ageing, provided exposure is moderate.

This view is heresy in the world of dermatology and Holick has suffered the equivalent of excommunication for his views. His own university has disowned him and the American Academy of Dermatology has condemned him as irresponsible, saying that going into the sun for its health benefits is like smoking to combat anxiety.

So what happened to academic freedom? Is it not the business of professionals to challenge the prevailing orthodoxy? Whatever you may think of Holick's views, he has researched the subject for many years and has occupied a post at one of America's top universities. He cannot be dismissed as a charlatan or an alternative practitioner with freakish ideas. His arguments demand a response - but instead his superiors at Boston University have opted for the sledgehammer tactic of trying to silence him.

Unsurprisingly, their tactic has backfired: Holick's sacking has been widely reported and has succeeded in drawing even greater attention to his book. Although he has been removed from the dermatology department, he continues to run the university's vitamin D laboratory and retains his salary, so his sacking is little more than symbolic.

Even so, it augurs ill for medical debate. Holick's aim, as stated in the preface to his book, is to "put society's attitude towards sunlight into proper perspective". He is not advocating tanning, he says, but he is recommending that people need a "certain amount of sun exposure to be healthy". That amounts to a few minutes a day (depending on skin type), unprotected by hats, shirts or sun cream, to allow the skin to manufacture the necessary vitamin D. In winter, or for indoor workers, this may mean using a sun lamp. Holick's thesis is that lack of sunlight, suffered especially by populations in northern climes, such as the UK, is associated with a host of conditions including cancer, heart disease, high blood pressure, diabetes, multiple sclerosis and depression.

You may question his evidence for this claim, as the American Academy of Dermatologists does: it says we can get all the vitamin D we need from diet, and sunlight is a proven carcinogen. One can understand, too, why the Academy is anxious to speak with one voice on this important issue, in the face of the rapid rise in melanoma over the past three decades.

It has to be acknowledged also that Holick has one or two conflicts of interest. Although he does not advocate tanning, he has links with the Indoor Tanning Association (his book was launched at one of their events) and has been promised $150,000 funding by them for his research. On the face of it, however, this does not look different from the funding that drug companies put up for researchers to run trials - a practice ubiquitous throughout medicine.

More worryingly, he also uses his book to promote "Dr Holick's new treatment for wrinkles" - a cream which he hopes to have on the market in "three to four years".

Nevertheless, what remains incomprehensible is the refusal of Holick's masters to engage in the debate about the risks and benefits of the sun. This is not an empty debate. In the UK questions have been raised over whether the dangers of sun exposure have been overdone. Neil Walker, chairman of the UK Skin Cancer Prevention Working Party and Consultant Dermatologist at Churchill Hospital, Oxford, has warned that telling people to avoid the sun entirely is "draconian and unnecessary".

Holick says he is not advocating sun worship. but a common-sense approach to the sun, "something often in short supply in modern America's approach to health". Sadly, it appears to be in short supply in Boston University, too.