It's common for men and women to have a STD without any symptoms. So you might not know you have one. Even if you don't have symptoms, you are still contagious and can pass the disease onto your partner. STDs, including the ones that don't cause symptoms, can cause serious problems with your health later on. They can cause PID (pelvic inflammatory disease), infertility and even cervical cancer . STD testing is recommended to anyone who has had sexual relations with one or more partner. It is even more important to get tested if you have one or more signs of an STD.
Why is such a sensitive and delicate body part just hanging there in the open? The placement of the testicles is inconvenient, but absolutely necessary. The testes’ job is to produce sperm, and sperm are very fragile. They’re extremely sensitive to high and low temperatures, and must be kept away from the rest of the body and relatively exposed to maintain the right climate. They can handle human body temps for only one to four hours, or the average amount of time it takes them to travel through the female reproductive tract and fertilize an egg. Internal testes or any type of significant shielding for them would heat them up too much, too early and make them drop out of the race well before reaching the egg, rendering them useless.