Aesthetics are usually the driving factor for most body art (and we could write a whole other article on the sexual motivations behind genital piercings), but some experts believe that choosing the location may have an impact. This mainly has to do with the theories behind meridian lines.
Meridian lines, or pathways, are a teaching in TCM that stipulates everything in the body is connected, and energy in the body can move through these pathways. The pathways correspond to different major organs, including the liver, heart, lungs, and so forth. The theory goes that when you get piercings along these meridian lines, you can disrupt the energy flow of the body—and that can affect the specific body parts associated with that meridian line.
For example, the conception vessel, which can be traced from the mouth to the bottom of the trunk. According to Melissa Skelly, LAc, licensed acupuncturist, acupoint specialist, sound healer, and owner of The Zen Den Center, "[I believe] piercings in the navel area—the conception vessel—can affect fertility."
Another example is how tongue piercings may cause stomach and digestive issues: "There have been reported issues with tongue piercings and digestive issues," says Dan. TMC theory dictates this is likely due to the piercing along the stomach meridian line; and compared to other piercings, there is also research to suggest this to be true; however, the researchers were unable to conclude it had to do with the piercings rather than other confounding factors.
We must note, of course, that as of yet, there is no scientific evidence to back these claims up, however. And in the end, most areas of the body may have more of a personal or even historical significance (piercing has existed for centuries in many different cultures) more than a physiological one. But if you have concerns, always do your homework on the potential side effects of a specific location.