Phoenix is witnessing explosive growth in the medical field. Here’s a look at five new cutting-edge facilities that are leading the way. By Susan Regan Celebration Stem Cell Centre 3495 S. Mercy Rd., Bldg. 14, Gilbert, 480-722-9963, celebrationstemcellcentre.com One of the latest debates among couples expecting a child is whether to store the newborn’s umbilical…