An international fertility conference and the association behind it are in disarray amid protests against Severino Antinori, the scientist who wants to clone a human being.
The Italian embryologist is facing peer pressure to back down from his high-profile plans, which have been attacked by figures such as Robert Edwards, the in vitro fertilisation pioneer, and Ian Wilmut, creator of Dolly the sheep.
They worry that cloning humans would be perilous. A high level of aborted and abnormal foetuses bedevils animal experiments.
Professor Antinori, head of the Raprui clinic in Rome and professor of assisted reproduction at Chieti University, retorted that there was "evidence that the risk of malformations is higher in animals than in humans".
This week, Professor Antinori was informed that he was being expelled from the Association of Private Assisted Reproductive Technology Clinics and Laboratories (Apart).
His opponents accused him of wrecking the association's Third World Congress that he was organising in Monte Carlo.
They complained that his "disreputable conduct" regarding cloning had injured Apart's reputation. They claim that more than half of the 77 speakers listed in the original programme are not expected to appear.
Wilfried Feichtinger, the association's president, wrote to Professor Antinori on Friday, stating that he should learn "there are certain rules within the scientific community and in medical associations that have to be respected".
Professor Antinori said the decision "was taken by people not representing the real managing board".
Leading scientists outside Apart have also voiced concern. Robert Edwards, whose picture hung in Professor Antinori's office, said cloning technology was not yet safe enough for humans, though he did not object in principle.
"Severino is so determined he's right that he can't see he is making a terrible mistake," he said.