Shauny, you're perpetuating folklore up there--or else you're a budding fiction writer. First of all, chewing gum does indeed partially dissolve and pass on through people's stomachs and intestines (the hydrochloric acid produced in our stomach lining can dissolve almost anything, including a wad of gum). Sometime when you study how the digestive system works, you'll learn that there's literally almost nothing that can't pass on through it. Its whole function is as a transportation system, in fact, and it's designed to pass its contents on.

Semen, too, starts being broken down by digestive enzymes in saliva the minute it comes into contact with someone's mouth, and it's broken down for the rest of its ride down the esophagus and into the stomach. It doesn't stay inside anyone's gut if it's swallowed. You'll have to trust me on this. Take a human physiology course sometime!