User blog comment:Justarandomguy/Are the Quarians Doomed also?/@comment-99.224.192.238-20120316042442/@comment-1900300-20120316043140

If that were the case every soldier in the Alliance would be dead. It is mentioned several times artifical upgrades were required during the Lazarus project for Shepard to live. The Commander is a cyborg, though EDI believes him human due to him not having any brain alterations, but that is not the definition. As a cyborg both organic and synthetic organs are needed for survival, so Shepard dies without his synthetic parts.

You are right about the quarians however, who have no synthetic upgrades.