Euthanasia is a way of relieving ill people's pain and save them form the tortures of their illness. Do we have the right to take people's life?

In the last years euthanasia has been a controversial topic. Some people think that euthanasia has to be prohibited, because it's not ethic to kill a person. They argue that, for example, with the approval of euthanasia, the number of homicides under the name of this practise would increase. 

On the other hand, a lot of people wants to legalize this practise. They state that everyone can decide to live or not. For them, living under determinate circumstances is worthless, so it's better to die than live. It's not fair to prolongate the life of someone who is about to die, suffering and having a bad life, an inexistent life. 

In my opinion euthanasia could be approved only in the cases in which the person who is sick is conscious of the illness and prefers to die. I think that it's better to die than to live quadriplegic, because you can't live your life, you can't run or play football or go out with friends. You always have to be on the bed and it's impossible to achieve happiness in a situation like this. This is not a life. But the law which approves euthanasia has to be a strict one, only for the cases where the consent is clear. That's my opinion...what's yours?