Steven W. Mosher is my go to guy on subjects like this. He heads the Population Research Institute (PRI), http://www.pop.org/ You can be sure that what he says is accurate.PRI was founded by the late Fr. Paul Marx, O.S.B. who also founded Human Life International &, God willing, will be declared a saint someday.
Al: Now that you mention it, I recognize Mosher as that bearded dude in the PRI videos.