There cannot be many leading academics who need to consider whether taking up a position at one of the world's most prestigious universities would put their personal safety at risk.
But when you are Professor Peter Singer of Monash's Centre for Human Bioethics and you are about to take up a post at Princeton University in August, the fact that American opponents of many of your views have shown themselves prepared to use violence makes this risk very real. He is well aware of this and, he admits, it bothers him.
When his appointment as De Camp Professor in Princeton's Centre for Human Values was announced last year, local newspaper articles appeared with the headlines: "Princeton's new hire: introductory Eugenics" and "Messenger of death at Princeton".
Among the views that Professor Singer's critics object to are his advocacy of euthanasia, not only for terminally ill patients but also for babies born with such severe disabilities that they would have no quality of life; his support for experimentation on human embryos in vitro; and his championing of the ethical treatment of animals. Indeed, his 1975 book, Animal Liberation, has been credited with founding the modern animal rights movement.
"My underlying ethical position is broad utilitarianism - essentially, we should try to reduce suffering and increase happiness as much as we can," he explains. And he does not see any moral difference between human beings and other living things. What matters is a creature's ability to think and feel - in particular, he says, its "capacity to suffer". This is why he has argued in favour of experimentation on IVF embryos, which he claims cannot suffer, while opposing unregulated experimentation on animals, which can suffer and therefore have rights.
Professor Singer says he has stayed at Monash since 1977 because it was "a good place to work", and because it supported his proposal in the early 1980s to set up the first bioethics centre in Australia. In fact, it was a member of Monash's medical staff, Associate Professor Bill Walters, who first persuaded Professor Singer to expand his main interest in philosophy, which he had studied at Melbourne and Oxford universities, to include human bioethics.
Dr Walters had said in a lecture back in 1977 that debate about the then proposed IVF program shouldn't be restricted to doctors, scientists and religious leaders - it should involve lawyers and ethicists as well. "What ethicists?" thought Peter Singer. And the rest, as they say, is history.
As Peter Unger, professor of philosophy at New York University, wrote in The Wall Street Journal, "This world-renowned Australian may well be the most prominent professor his country has ever produced; by many measures, he's the most influential ethicist alive."
But after two decades and dozens of books, articles and radio and television appearances, Professor Singer is leaving: "Everyone in Australia has heard my views - but a few hundred million Americans probably haven't." He says he was drawn to America by "the challenge of influencing opinion in a much bigger, and globally influential, nation".
The move to America certainly doesn't reflect any belief on the professor's part that his work in Australia is done. He claims that public debate in Australia on bioethical subjects has become sensible and broadly based - certainly more so than in the US. Practical results, however, have been mixed, such as when the world's first legal voluntary euthanasia program in the Northern Territory was overridden by the Federal Government. He welcomed Victoria's pioneering legislation on IVF, but believes things have since "gone backwards" under the Kennett Government.
Professor Singer thinks some progress has been made on animal rights in Australia, though not nearly enough: "Unregulated animal experimentation is largely a thing of the past, but we've made no progress on farm animals - we lag way behind the European Union, for example". Still, he says, increased public awareness of animal rights means "things should improve in the 21st century".
Asked what will be the greatest challenge to human bioethics next century, he replies: "Genetics - genetic testing, screening and engineering."
When assessing his own contribution, Peter Singer is modest: "On human bioethics, I helped make people aware of different perspectives on various issues and helped get philosophers and the public interested in the debate." On animal rights, he says, his achievement was to "kick things along a bit faster".
It will be interesting to watch what happens when Professor Singer starts to kick things along in the United States.
Professor Peter Singer has been often been at the centre of heated public debate.