A bill aiming to give terminally ill people the right to die has been published at the Scottish Parliament.
MSP Margo MacDonald, who has Parkinson's disease, brought the bill to make it legal for someone to seek help to end their life.
It is not illegal to attempt suicide in Scotland but helping someone take their own life could lead to prosecution.
The MSP wants terminally ill people to be able to ask willing doctors to help them die at a time of their choosing.
The independent Lothian MSP's End of Life Assistance (Scotland) Bill would allow people whose lives become intolerable through a progressive degenerative condition, a trauma or terminal illness to seek a doctor's help in dying.
The bill has also proposed a series of safeguards to prevent abuse of the legislation, should it become law.
It also proposes that doctors with religious or moral objections would not be obliged to help any patient end their life.
Launching the bill, Ms MacDonald said: "There are many other people that have progressive degenerative conditions that are much more vicious than mine.
"This bill is meant to redress that unfairness to give those people the autonomy to exercise some control over how they die to give them the legal right to seek assistance and to protect the people who would give them assistance."
Pro-life campaigners have strongly opposed the idea of assisted suicide.
The Care Not Killing association has urged MSPs to proceed with "extreme care and caution" when considering the bill.
However, Sarah Wootton, chief executive of Dignity in Dying, said the bill was an "important opportunity for a much-needed debate".
She said: "People want choice and control at the end of life. Without a safeguarded law regulating choice over how and when we die, many people will take matters into their own hands.
"This problem must be addressed, otherwise we are effectively condoning people travelling abroad to die, 'mercy killings' and suicides behind closed doors."
In order for the bill to become law, it would have to be scrutinised by a Scottish Parliament committee system, before facing several votes
Unlike the majority of proposed legislation which comes before the Scottish Parliament, the bill would be decided by MSPs in a "free vote", rather than on a party basis.
In England, the director of public prosecutions has indicated he was unlikely to take legal action against those who assist the suicide of friends or relatives who have a settled and informed wish to die.
No such guidance has been given in Scotland, but Ms MacDonald says public opinion on assisted suicide was changing.