Last August, Pastor Rick Warren stumped then-Sen. Barack Obama with a seemingly simple question.
"At what point," asked Warren, "does a baby get human rights, in your view?"
"Well, I think that whether you're looking at it from a theological perspective or a scientific perspective, answering that question with specificity, you know, is above my pay grade," said Obama.
It turns out, however, that an even simpler question once stumped the very person Obama now pays to give him advice about science: When does a human become a "human being"?
John P. Holdren is director of the White House Office of Science and Technology Policy. In 1973, he co-authored a book -- "Human Ecology: Problems and Solutions" -- with Paul Ehrlich and Anne Ehrlich.
At the time, Holdren was a researcher at California Institute of Technology and the Ehrlichs were professors at Stanford. Paul Ehrlich was already well known for having authored "The Population Bomb," a 1968 bestseller that The Washington Post later said "launched the popular movement for zero population growth."
Holdren's credentials are stellar. He earned a doctorate from Stanford, taught at California and Harvard, and was director of the Woods Hole Research Center -- where his co-authorship of "Human Ecology" is cited in his online curriculum vitae.
"Human Ecology" painted an apocalyptic vision.
"Human beings cling jealously to their prerogative to reproduce as they please -- and they please to make each new generation larger than the last -- yet endless multiplication on a finite planet is impossible," the authors wrote in the opening chapter. "Most humans aspire to greater material prosperity, but the number of people that can be supported on Earth if everyone is rich is even smaller than if everyone is poor."
On page 235, while making an argument for legalized abortion, the authors use language that on its face says a child "will ultimately develop into a human being" -- after it is born.
"To most biologists, an embryo (unborn child during the first two or three months of development) or a fetus is no more a complete human being than a blueprint is a building," they wrote. "The fetus, given the opportunity to develop properly before birth, and given the essential early socializing experiences and sufficient nourishing food during the crucial early years after birth, will ultimately develop into a human being. Where any of these essential elements is lacking, the resultant individual will be deficient in some respect."