Almost half of the world faces the same demographic problem: not enough babies are being born to keep up with an aging population. As a result, countries have been trying all kinds of measures to get their citizens in the mood for procreating. Japan is spending about ¥3 billion ($29.3 million) on matchmaking events and robot babies that might inspire couples to want one of their own. Saucy ad campaigns in Denmark and Singapore remind couples that they have a civic duty inside as well as outside of the bedroom.