A decade-old euthanasia law was used in a mercy-killing pact by deaf Belgian identical twins who died after they realized they were gradually going blind, Flemish media reported.
In what was presented as a unique case, the 45-year-old men from the Antwerp area who shared a bedroom all their lives began to encounter problems with their sight several years ago, Het Laatste Nieuws newspaper said according to French-language reports.
Brussels doctors backed the twins' demand to be allowed to die on December 14 last year, even though neither man was suffering from any terminal illness.
Days after their death, Belgian Socialists submitted a proposed law change that would also allow minors and Alzheimer's sufferers to seek permission to die.
Belgium was the second country in the world after The Netherlands to legalise euthanasia in 2002.
Some 1,133 cases -- mostly for terminal cancer -- were recorded in 2011, according to official figures.