The Clearlight Catholic Homepage 19 weeks after conception: Babies can survive outside the womb. 14 weeks after conception: All organs neccessary to feel pain are in place. 42 days after conception: Unborn children respond to stimuli. 40 days after conception: Children's brain waves can be measured. 21 days after conception: Unborn children have a beating heart. At conception: A unique individual is created. There will never again be another just like them.