The only answer that has any chance against against the information saturation kids face these days is to talk openly with kids, early enough and often enough and unflinchingly enough that you set the precedent of being the safe place they can go to ask their difficult questions. It has to happen starting when they're 2 or 3, and they ask you where babies come from and instead of freaking out and deflecting, you give facts commensurate with their ability to understand.