Millions of women today face a major decision whether or not touse estrogen during and after menopause. They include not onlywomen who have ceased menstruating entirely, but also womenin their forties and early fifties whose age and menstrual cyclechanges indicate the approach of menopause. Menopause, bydefinition, means the last menstrual period, but many people usethe term more loosely to include the years leading up to andfollowing the last period. The number of women facing thisimportant decision is growing dramatically as the large popula-tion increase of women born after World War II reaches midlife.In fact, the number of women between the ages of 45 to 54 isexpected to grow 73 percent between 1990 and 2010, according toa recent article published in American Demographics (35 millionwomen in the United States are currently menopausal). Forwomen in their menopausal and postmenopausal years, the main-tenance of good health and well-being, as well as prevention ofdiseases of aging such as heart disease and cancer, become majorissues. The role of estrogen in attaining these goals is a centralissue for most midlife women.