The 6 Most Common STDs in Men Could you have an STD and not even know it? If you’re sexually active with more than one partner, there is an increased possibility that you can be infected with a sexually transmitted disease but remain symptomless. In fact, many of the most common STDs can fester for weeks, months and even longer without creating any warning signs. This can be dangerous not only for yourself, but also for your partners, since you can be spreading an ailment if you don’t take the proper precautions. The following is a look at some of the most common STDs among men, what symptoms (if any) they typically cause and mindful information about what could the infections lead to if they are not treated early and effectively: