Stop. Don't throw out that deep chest freezer just yet. You may need to freeze Granny. In the next century you should be able to thaw her out and introduce her to the great, great grand children. At least that's the theory behind cryonics - the science of freezing and thawing human tissue.

For many, being suspended for 50 or 100 years might seem creepy, but for the 400 members of the Alcor Foundation in Silicon Valley, it's the welcome chance to get a second opinion from the doctors who may know a little more in the future.

"Most people think of cryonics as freezing the dead," said Dr Ralph Merkle, a prominent scientist with Xerox's PARC research facility and Alcor board member. "But in 1948 if your heart stopped you would be pronounced dead. Now doctors will put you on life support."

Dr Merkle and other prominent scientists such as nanotechnology pioneer Dr K. Eric Drexler, and computer science guru Dr Marvin Minsky of the Massachusetts Institute of Technology along with medical doctors and private members believe that at some stage in the not-too-distant future science will find the means to cope with cryonics.

See, freezing is not a problem. They have that solved. And sorry, your deep chest freezer is no good because Alcor freezes people in liquid nitrogen.

The problem, it seems, is thawing them out later.

Currently there is no way to thaw humans out without damaging the cells.

However, Dr Merkle believes that it will not take too long to solve this problem.

"It is worth pointing out that a fairly wide range of simple tissue types have been successfully frozen and thawed," said Dr Merkle. "Including very early human embryos, sperm, skin, bone, red and white blood cells, bone marrow, and others."

How do they do it? They use anti-freeze or glycerol to reduce freezing damage. But it is not perfected yet.

So the 30 people Alcor has frozen may have to wait a while before they can be revived.

In fact, we may have the science figured out before we have the paperwork done.

Alcor does not regard its customers as dead. At least not in the physical sense. In a legal sense they are quite dead. This poses all sorts of legal and financial problems.

How do you un-declare someone as dead?

What happens to the death certificate or their social security number for that matter. Furthermore, how can the people frozen take their money with them? So that they don't wake up broke. Or worse, in debt due to the rising medical costs of keeping them frozen?

"We are trying to solve these problems at the moment," said Dr Merkle. "The money can be held in some sort of trust fund but the problem is that if you are declared legally dead how can you inherit it."

Alcor may have to work to change the law to redefine different states of death. Dead asleep and dead forever, perhaps.

Surprisingly, the cost of being frozen is not too bad. Less than the cost of a new BMW. Most people use life insurance to pay for their cryonic suspensions. Currently, Neurosuspension (just the brain) costs $50,000 (€47,842) for members in the US, and $60,000 for those in other countries.

Similarly, Whole Body Suspension costs $120,000 or $130,000. However, Alcor must be designated as owner of the policy.

Indeed, it's safe to assume that cryonics is in its infancy and will become more popular in the next millennium.

During a recent conference in Silicon Valley, Dr Drexler suggested that ecological organisations should freeze organisms and species that will become extinct.

"I suggest that we collect large samples of genetic material from the rapidly disappearing rain forests, soil samples, trees, and plant life, freeze them and revive them in the future when future generations will appreciate them," said Dr Drexler.

"That way we can ensure biodiversity in the future."

Still, I think I would prefer to be cremated.

Niall Mckay can be reached at irish-times@niall.org