If you’re a man in China between 20 and 45, the government has a message for you: For the sake of your country, please donate sperm. China’s sperm banks are facing severe shortages, for a variety of political and cultural reasons. Comparatively few Chinese men offer to donate, and a study found that almost half of those who do volunteer are screened out. Now that government policy allows more Chinese couples, including older couples, to have a second child, officials are concerned that the sperm shortages will get much worse — and they are doing everything they can to find new recruits.