Members of cryonics organisation Alcor Life Extension Foundation wear a metal bracelet or necklace wherever they go. On it are the words "no embalming" and "no autopsy", indicating to medical professionals that there are other plans for their bodies after death.
The plan involves cryonics - a low- temperature preservation of humans after death in the hope of reviving them in the future.
The process was in the news lately, after Matheryn Noavaratpong, a two-year-old from Thailand who died of brain cancer, became the youngest person to be cryonically preserved and stored by United States non-profit organisation Alcor.
Such facilities - two in the US and one in Russia - seem to be gaining a small following of members from across the globe. Some prominent names such as talk show host Larry King and TV personality Simon Cowell have said they intend to freeze themselves after death.
But many scientists have all but called cryonics a hoax, laying out the scientific limitations and labelling it a pseudo-science at best.
In the US, the cost of whole-body cryopreservation starts at around US$60,000 (S$80,000).
Part of the money is put into a trust or investments, and the earnings are used for ongoing care and the cost of future revival.
People are also advised to set up trusts for themselves to provide for their future selves.
Often, people pay for their cryopreservation through life insurance and for an additional fee, Alcor even gives them the option to store their personal items such as photos or journals in a box which will be kept in a salt mine.
The Cryonics Institute, based in Clinton Township, Michigan, has 132 patients in suspension, while Alcor, in Scottsdale, Arizona, has 134 - with the Thai toddler being the latest addition. But this is just the tip of the iceberg, so to speak.
More than 2,000 people have signed up for cryopreservation with these two main US companies, including about a dozen Asians from countries that include Singapore, China and Thailand.
Ms Marji Klima, an administrator at Alcor who spoke with The Sunday Times, said membership has been "fairly steady through the last 20 years or more" but there has been a recent spike in interest due to the media and rapid advancements in medicine and nanotechology.
"More people are learning about it because of the scientific advancements that are being reported," she said.
The process involves removing blood from the body and introducing a solution that prevents freezing. Alcor "patients" are then stored in liquid nitrogen at a temperature of minus 196 deg C.
Cryogenic Society of America executive director Laurie Huget was quick to draw the distinction between cryogenics and cryonics.
"Cryogenics (which deals with extremely low temperatures) is a legitimate, long-recognised technology that supports so many areas of science and industry. It is not involved with pseudo-science such as cryonics," she said. The whole idea of cryonics was first touted by a physics teacher named Mr Robert Ettinger, who published a book called The Prospect Of Immortality in 1964. He subsequently founded the Cryonics Institute in 1976, which promotes the concept and also provides storage facilities.
The book also prompted Mrs Linda Chamberlain and her husband, Mr Fred Chamberlain, to set up Alcor in 1972.
Mrs Chamberlain, 69, told The Sunday Times that Mr Chamberlain is a neuro patient - meaning only his head and brain are preserved - and she will also be preserved in the same way when she dies.
According to her, chances of resuscitation are pretty high. "Based on the current advance of science and technology, I feel certain that our chances of being resuscitated within the next 50 years are very good," she said.
"If we are not resuscitated, I feel certain the problem will not have been with technology but with social or political problems, such as war."
But many scientists and critics largely disagree with the science behind cryonics.
"At the moment, the chances of resuscitation are pretty close to zero," said American science writer Michael Shermer, who has a doctorate in the history of science. I would say they are probably a century or two away from figuring out cryonics."
While cryonicists argue that human embryos are frozen and used again, Dr Shermer, who publishes Skeptic Magazine, said: "Freezing single cells or an egg is one thing, a dog or a human is more complex."
He added that "thawing" a human would be like thawing a frozen strawberry. "It would just be mush," he said.
And with regard to nanobots repairing cell tissue, which is what cryonicists believe should be possible in the future, he said: "In principal, it could work, but we are not even close in the field of nanotechology."
So why do people still sign up to be suspended in cryostats - cylindrical tanks which their loved ones can visit like graves in a cemetery?
Dr James Hughes, executive director for the Institute for Ethics and Emerging Technologies, said: "If you believe that technology in the future will be able to do more than the technology today, then signing up for cryonics is a rational bet on staying alive."
Added Dr Shermer: "It's a probability argument. With cremation, saving your DNA and memories is 100 per cent sure to fail, with cryonics, it's not quite 100 per cent."
"But I'm a sceptic because there is no evidence yet," said Dr Shermer.
This article was first published on April 26, 2015.
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