Legalising assisted dying would provide more protection and choice for the living, the MP who introduced the bill in the House of Commons has said.
Rob Marris said most people would never choose an assisted death but it was right to give people the option to die "a dignified and peaceful death at a time and place" of their choice.
"I and many other people would find it comforting to know that the choice was available," he said.
"If the exercise of a choice does not harm others we should allow that choice."
Following Mr Marris' opening remarks, Conservative MP Caroline Spelman said the proposals would legitimise suicide and the involvement of others in it.
MPs have overwhelmingly rejected the Assisted Dying Bill, despite apparent public support.
MPs are set to vote on the right to die for the first time in 20 years today as controversial laws are subject to a landmark debate.
Described by the Archbishop of Canterbury as one of "the biggest dilemmas of our time", MPs are preparing to debate assisted dying.