UK cosmologist Prof Stephen Hawking has publicly said he backs the notion of assisted suicide for people with terminal illnesses.
In an interview with the BBC he said: "We don't let animals suffer, so why humans?"
Prof Hawking, who has progressive motor neurone disease, has in the past been less candid about the idea, saying "while there's life, there's hope".
But he stressed that there must be safeguards to prevent abuse.
Prof Hawking himself was once put on a life support machine which his wife was given the option of switching off.
When asked if family members of those who wish to die should be able to assist without fear of prosecution, Prof Hawking said yes.
But he added: "There must be safeguards that the person concerned genuinely wants to end their life and they are not being pressurised into it or have it done without their knowledge or consent as would have been the case with me."
Prof Hawking, 71, is one of the world's most famous scientists.
Aside from his academic accolades, the professor learned to adapt to life after being diagnosed with motor neurone disease and given two years to live when he married his first wife, Jane, in 1964.
Only 5% of people with the form of MND that he has - a condition called amyotrophic lateral sclerosis (ALS) or Lou Gehrig's disease - survive for more than a decade after diagnosis.