The clinic's method of treatment involves injecting patients with stem cells taken from babies aborted between seven and ten weeks old.
It is a technique, says Dr Minger, that has no credible research to back it up, and that raises disturbing questions about how the cells have been 'harvested'.
"The problem is, I am not sure how the cells are prepared," he says. "A six-week-old embryo can be just 1cm from head to foot, so it's difficult to dissect tissue from it. They may just homogenise the whole embryo." That's a polite way of saying that the aborted babies could have been liquidised.
Dr Minger was especially troubled that as well as offering unproven therapy to patients with degenerative diseases - at up to £10,000 a time - the clinic was running a lucrative sideline in offering stem cell treatments to reverse the effects of ageing.
The firm boasts that such treatment can lead to everything from improved fitness and a better sex life to greater mental capacity and enhanced sleep patterns.
"I find it very distasteful that they are used for beauty treatments," says Dr Minger. "As far as I can tell from what's been published, a lot of people go to this clinic in Barbados feeling a bit run down, or that their skin has just lost some elasticity, and they are getting 'smoothies' or perk-me-ups."
The stem cells used in these techniques are bought by IRM from the Ukraine. They are said to be taken from aborted foetuses, with the mothers' consent. But could there be a link with the Ukrainian mothers who believe their babies were deliberately taken from them?
I travelled to Barbados to speak to one of IRM's senior doctors, Shami Ramesh.
Initially, I feared my journey was in vain. As I approached the 170-year-old colonial building where the clinic is based, I found the gates were padlocked - I was told by Dr Ramesh that I would have to come back in January.
But eventually I managed to persuade him to come to my hotel, where he said he could show me evidence of two studies that proved the treatments work.
This "proof" turned out to be one study of a single patient with motor neurone disease and another of eight cardiac patients. The numbers were too small for proper analysis and the data had not been published in any reputable peer-reviewed journal.
But Dr Ramesh's faith in the treatment was striking. "Foetal stem cells work," he said. "If patients were not getting value for money they would not be coming back to us for second and third infusions."
Then our conversation turned to the main part of my inquiry: how could he be certain the stem cells the clinic was using had indeed come only from aborted foetuses in the Ukraine - a country where there's very little regulation over issues like consent from donors.
Was it possible that the cells had, in fact, been harvested from fullterm babies without any consent from the parents?