The Phase was a period in the life of female Betazoids, during which she becomes fully sexual. This occurs in mid-life, and is characterized by a quadrupling of the sex drive. In some cases, the female's telepathic abilities are impeded by the Phase.
- In "Manhunt", Deanna Troi compared the Phase to menopause, which marks the end of a human woman's ability to conceive children. However, Lwaxana did become pregnant several years later. (DS9 episode: "The Muse") As Lwaxana admits in this latter episode that she had thought she was too old to have more children, it's possible the menopause analogy is apt, and Lwaxana's case is an anomaly.