Which of the following conditions is characterized by the inability to achieve or maintain an erection?

Erectile dysfunction is characterized specifically by the inability to achieve or maintain an erection sufficient for satisfactory sexual performance. This condition can arise from various physical, psychological, and lifestyle factors, including underlying health issues such as cardiovascular disease, diabetes, stress, anxiety, or relationship problems. It is important to distinguish this condition from other sexual health issues.

For example, premature ejaculation involves the timing of ejaculation rather than the ability to achieve an erection, while dyspareunia refers to pain during intercourse, which does not directly relate to erectile function. Low libido, on the other hand, is associated with a decreased interest in sexual activity rather than the physical ability to maintain an erection. Understanding these distinctions helps clarify why erectile dysfunction is the correct answer to the question regarding the inability to achieve or maintain an erection.