Dr. Mache Seibel (MAYsh Sible rhymes with bible) is a 25-year Harvard Medical School faculty member. He is author of two best-selling books, The Estrogen Window and The Estrogen Fix, founding publisher of The Hot Years magazine (HotYearsMag.com), the #1 digital magazine for midlife women, and Best Menopause Blog of 2020 blogger (DrMache.com/blog). Before transitioning his career to focus on menopause, Dr. Mache was a leading expert in infertility and performed some of the first In vitro fertilization successes in the United States.