"The world today has 6.8 billion people... that's headed up to about 9 billion. Now if we do a really great job on new vaccines, health care, reproductive health services, we could lower that by perhaps 10 or 15 percent." -- Bill Gates (in public speech with published video) I saw the video, the quote is correct. Don't have link handy, find it yourself. Did he mis-speak? Maybe. He never corrected it, despite it going viral.