Fertility expert Lord Winston has accused Prince Charles of raising unfounded scientific "scares" following comments he made in a newspaper.
Lord Winston has called for a careful discussion of scientific issues
The Prince used an Independent on Sunday (IoS) article to warn against the possible risks posed by nanotechnology.
Lord Winston told the BBC's Today programme it was "very unfortunate" the Prince had chosen to raise the spectre of a thalidomide-style disaster.
He added that "much more informed debate and dialogue" was needed.
In his article, the Prince acknowledged the "triumph of human ingenuity" involved in manipulating materials one-millionth the size of a pinhead.
Nanotechnology is concerned with engineering objects and working devices from individual atoms and molecules.
But he quoted retired Cambridge University engineering professor John Carroll, who said it "would be surprising if nanotechnology did not offer similar upsets" as thalidomide, the morning-sickness drug which led to thousands of babies suffering birth defects.
"What is troublesome to me is that, again and again, there is a real opportunity for His Royal Highness - who I think is an honourable and nice man - to be helpful, and what is not happening is a careful discussion of the issues in science," Lord Winston told the BBC's Today programme - although he admitted he had yet to read the Prince's IoS article directly.
"We are living in a very science-suspicious society and to raise these kinds of spectres without really quite explaining why he is so worried, I think, is very unfortunate.
"Yet again, it is another example of where he has raised science scares and yet hasn't justified raising them.
"What is needed is not this kind of criticism, but a much more informed debate and dialogue in society and I don't think he has added to that dialogue by making unformed accusations which are not understandable."
The Prince's comments come just weeks after he was criticised for promoting the possible benefits of alternative treatments for cancer - something that Lord Winston said had "badly damaged" patients by raising unnecessary anxieties.
"With the cancer thing, the truth is that Prince Charles has never justified any serious evidence that these alternative therapies for cancer actually work," Lord Winston continued.
"In consequence, many people may be very badly damaged because they are worried as a result and I think that is very, very unfortunate."
The environmentalist Jonathon Porritt, a close adviser of the Prince, told Today: "Prince Charles is calling for exactly the kind of informed intelligent debate that Lord Winston has recommended.
"He has suggested it should involve not just the elite of today's scientific
establishment, but should also involve the general public, and more effort should be made to explain a very complex and technical area of concern.
"That, it seems to me, is a wholly legitimate contribution to the kind of debate that we all feel we now need."
Prince Charles' concerns about nanotechnology sparked a row last year.
In the paper he writes: "My first gentle attempt to draw the subject to wider attention resulted in 'Prince fears grey goo nightmare' headlines."
He says he never used the expression "grey goo", adding: "I do not believe that self-replicating robots, smaller than viruses, will one day multiply uncontrollably and devour our planet.