"地球防卫少年" (Chikyu Bouei Shounen, meaning "Earth Defense Youth") doesn't seem to be a widely known title or franchise. It's possible that you might be referring to a specific anime, manga, game, or other media that I'm not familiar with. Could you provide more details or context about what you're looking for? This could include the source material, any characters, plot points, or where you heard about it. With more information, I can try to help you find more accurate and relevant information.