When the Palestinian stem-cell scientist Jacob Hanna was stopped while entering the US last May, airport customs agents took him aside and held him for hours in secondary," a back office where you don't have your passport and can't use your phone. There were two young Russian women and a candy machine in the room...

This is today's edition ofThe Download,our weekday newsletter that provides a daily dose of what's going on in the world of technology. The astonishing embryo models of Jacob Hanna Instead of relying on the same old recipe biology has followed for a billion years, give or take, stem-cell scientist Jacob Hanna is coaxing the beginnings...