The world's richest man, Jeff Bezos, is reportedly investing in anti-ageing technology that could extend the average human lifespan by up to 50 years. Bezos is said to be one of several billionaire investors in Altos Labs, a Silicon Valley tech firm working on experimental - and potentially dangerous - new life extension technologies.
The new company has hired dozens of experts from top universities to research how cells age and how to reverse that process.
This "reprogramming technology" aims to return normal cells to a "primitive" stem cell state - that is how cells act when someone is first born - in order to heal and regenerate.
Among those hired is Spanish scientist Juan Carlos Izpisua Belmonte. He is infamous for his controversial work on mixing human and monkey embryos, and predicts he will be able to extend life expectancy by 50 years.
When Belmonte tested his findings on live mice, they showed signs of age reversal - however, some mice developed deadly tumours called teratomas.
Altos Labs hopes to now further this and other research until it can reverse ageing in every part of the body - but it may be decades before the technologies are fit for human trials. Bezos is said to have been interested in the field for some time, after previously investing in anti-ageing company Unity Biotechnology.
In a final letter to Amazon shareholders, Bezos also quoted the atheist Richard Dawkins, saying: "Staving off death is a thing you have to work at... if living things didn't work actively to prevent it, they would eventually merge into their surroundings, and cease to exist as autonomous beings."