Most people accept dying of old age as a natural part of life, but some scientists insist we could be living much longer.

Geneticist Aubrey de Grey of Cambridge University figures humans could live to 1,000 years with the help of biotechnology and various therapies.

Reaching that goal, however, will take at least 10 years of mouse trials and another 15 on humans.

"There's an enormous amount of uncertainty," said de Grey, who gave an anti-aging lecture at a packed 160-seat theatre in Edmonton. "I'd say we have a 50-50 shot of getting there within 25 years from now."

The goal itself isn't far-fetched, said Richard Stein of the University of Alberta's Centre for Neuroscience. If it doesn't happen in 25 years, then maybe in 50 years.

"Most of the things he's saying are absolutely true in terms of what we know about the biology of the system," said Stein.

De Grey's team wants $100 million a year to fund its research. Governments aren't willing to pay, so it's appealing to those attending anti-aging talks to pay $1,000 per year.

Others are more cautious, warning the ethics of a non-aging population need to be considered carefully.

Chemist Hariyanto Darmawan of the University of Alberta agreed it's realistic to fight aging in 25 years. "But ethical issues will take longer than that. The politics, too."