When it comes to sexually transmitted infections (STIs), it is important to understand that they are not always caused by sexual intercourse. Some infections develop due to an imbalance in the body's natural flora.

STD Yeast Infection: This results from the overgrowth of yeast fungus in the body. It can be triggered by various factors such as the use of antibiotics, pregnancy, or diabetes.

STD Fungal Infection: This refers to infections caused by various fungi, and they are not always sexually transmitted. They may occur due to a weakened immune system or other underlying conditions.

STD Bacterial Infection: These infections are caused by bacteria that often enter the body through sexual contact. Common examples include Chlamydia and Gonorrhea.

Viral Sexually Transmitted Infections: Examples include HIV and Herpes. These infections are caused by viruses and are often lifelong, although they can usually be managed with appropriate medication.