What is one key factor in avoiding sexually transmitted diseases?

Abstinence is the most effective key factor in avoiding sexually transmitted diseases (STDs) because it completely eliminates the risk of exposure to pathogens that cause these infections. When a person refrains from any sexual activity, they avoid direct contact with bodily fluids or skin that could potentially harbor diseases. This approach is particularly relevant for individuals who are not in a mutually monogamous relationship, where both partners have been tested and are free of STDs.

In terms of the other options, increased sexual activity, inconsistent use of protection, and engaging in multiple partnerships all increase the likelihood of exposure to sexually transmitted infections, making them less effective strategies for disease prevention. In contrast, abstinence stands out as the only method that guarantees complete protection against STDs, emphasizing the importance of understanding personal choices and their consequences with regard to sexual health.