Abstract: The invention provides a molecule that inhibits or prevents an interaction between a Src family kinase and an androgen or estradiol receptor, for use in preventing or treating a non-cancerous condition in which an activity of AR and/or ER is a contributory factor in a subject, or for use in preventing or treating a cancerous condition in which an activity of AR and/or ER is a contributory factor in a subject who wishes to preserve fertility, or for use in preventing or treating a gynecological condition in which an activity of AR and/or ER is a contributory factor in a subject.