8 surprising medical conditions that could bar you from service Caitlin O'Brien 1 day ago U.S. Army Pfc. Shaundra Koch holds a stethoscope during a medical civil assistance program at the Nerkh District Center in the Wardak province of Afghanistan Oct. 21, 2009. It’s no surprise that service members must be in good physical shape to serve in the military. However, there are some medical conditions that you might not know can bar you from service. The military lays out certain physical requirements that those wishing to serve must meet, and recruits must undergo a medical exam. When joining, they must also disclose significant medical conditions.