Osteoporosis is a condition in which bones become porous (less dense) and weaker. It affects 10 million people in the United States: approximately eight million women and two million men. As bone weakens, people are more likely to experience fractures, especially in the spine, hip, and forearm. This causes pain, diminishes a person’s ability to function, and reduces quality of life. Anything that can lower the risk of osteoporosis and fractures has major positive public health implications. That’s why a new drug called romosozumab is getting a lot of attention.