captioning sponsored by cbs and johnson & johnson, where quality products for the american family have been a tradition for generations. osgood: good morning. i m charles osgood and this is sunday morning. we switched over to daylight saving time very early this morning. just six days from now, we ll be saying hello to spring. not a moment too soon for the millions of people who suffer from seasonal affective disorder. and then it s on to the gift of life. legacy of a woman who died in obscurity and whose remarkable contribution to medicine is only now being widely recognized. jim axelrod will have her story. reporter: in 1951 as henrietta lacks lay dying from cancer, researchers took a sample of her cells. they became the raw material for nearly every major medical advance in the past half century. they were used to help test the polio vaccine. in the first space mission, some of the first genes ever mapped. reporter: henrietta lacks and her immortal cells later on s