In this week’s Medical Discovery News by UTMB’s David Niesel and Norbert Herzog: Drinking milk might seem perfectly natural, but it’s actually anything but. Humans are the only species who retain the ability to digest milk after childhood, or at least some of us do. Up to half of adults worldwide don’t have the ability to break down lactose, the main sugar in milk, because their bodies stop producing the enzyme lactase after the age of 5. The column also appears in the Galveston Daily News.