Personalized World’s Best Immunologist Daddy Toddler Hoodie. My Daddy is the World’s Best Immunologist Toddler Hoodie - Pink has cute world’s best design with slogan for the son or daughter of an Immunologist. The Toddler Pullover Fleece Hoodie keeps little ones cozy and comfortable through all their adventures. Made with soft fleece and a smooth jersey-lined hood, it’s perfect for layering on chilly days. Ribbed cuffs and waistband help hold in warmth while side seam pockets add a touch of practicality for busy toddlers on the go.