Persistent genital arousal disorder affects women of all ages. It isn't known how many women are affected, because many women are embarrassed to speak with their doctors. Dr. Sandra Leiblum, former director of the Center for Sexual and Relationship Health at the Robert Wood Johnson Medical School in New Jersey and author of "Principles and Practices of Sexual Therapy," defines PGAD as an "intense feelings of genital congestion and sensations that are typically unaccompanied by any conscious awareness of sexual desire." She said the sensations can last for hours or even days and they are truly unwanted and intrusive.