In the Chamber of Representatives, also known as the lower house of Parliament, 86 lawmakers voted in favour, 44 against and 12 abstained. Most opposition parties supported it, as well as the governing socialists and liberals. One member of the public in the gallery shouted "murderers" in French when the vote was passed, Reuters reported.
Under the amendments, any terminally ill child can request euthanasia, but such a request would only be granted if the child was close to death and a team of psychologists, doctors and other medical professionals agreed that he or she was mature enough to understand the meaning of euthanasia. Any request would also require the approval of the parents.
"As a paediatrician, the first thing we want to do is cure children and babies and make them better as soon as possible," said Dr Gerlant van Berlaer, from the University Hospital, Brussels. "We're just talking about the things we cannot resolve. And then, even if it's not a positive solution, we have to have some solution so these children do not suffer."
For Dr Stefaan Van Gool, a paediatrician at the University of Leuven, the new laws in Belgium amount to "giving lethal injections to children". He was one of more than 170 paediatricians who signed an open letter this week urging Parliament to postpone its decision.
"I have never had such a type of question so I don't see the urgency," he told the Independent, adding that he also feared that vulnerable children could become victims of misinterpretations of the law: "If one opens the door, you have no control any more of what is going through this door."
Paediatricians in favour of the amendment agree that young patients requesting euthanasia are rare. But they are thankful they can now openly discuss all the options when such a request is made, knowing that medical teams and the relatives of the child need not fear legal action.
"I can bear them suffering if that's their wish; what I can't bear is that I can't talk about other solutions and discuss with my patients what they think about this," said Dr Jutte Van der Werf Ten Bosch, a paediatric oncologist from University Hospital, Brussels.
"That makes me feel that I'm a coward and I'm not giving them all the possibilities."
Helping people die
• Belgium, the Netherlands and Luxembourg are the only countries with legal euthanasia.
• Some nations, including Switzerland, permit assisted suicide.
• In the Netherlands, children as young as 12 can request assistance to end their lives.
•In Luxembourg the minimum age is 18.