Sexual transmission is the most common method of transmission for many infectious diseases, including HIV, syphilis, gonorrhea, and herpes. This mode of transmission occurs through sexual contact, such as vaginal, anal, or oral sex, with an infected individual. It is a significant concern due to the potential for widespread transmission and the risk of developing serious health complications. Safe sexual practices, such as using condoms and regular testing, are essential in preventing the spread of sexually transmitted infections.