 That's about only 8.5% of our country, and that's a 15-year low. That's just an abstract sort of demographic statistic that people don't necessarily think about. The U.S.'s selective service system requires men 18 to 25 to serve if need be. Congress could open that up to women as well. There's also growing concern about eligibility. More young people are taking medications for things like anxiety and ADHD. That can make medical clearance more challenging. With Military Matters, Alexandria Hoff, Fox News.