What’s the most common gynecological infection? It’s not yeast. It’s not viral vaginitis. It’s bacterial vaginosis, and it affects approximately 21 million U.S. women—or more than one in 10 of us—each year. Or that’s experts’ best guess; no major health organization has collected information on BV’s preva­lence in the U.S. since 2004. Thankfully, the majority…