Personalized Body Builder T-Shirt. Bio Engineer, body builder text with a strand of DNA is a humorous design for biological engineers. Fun gifts for bioengineers at birthdays, holidays and graduation. Wardrobe essential for looking good, 24/7. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar. Shoulder-to-shoulder taping. Double-needle stitched sleeves, bottom hem and front neck. Note: greys are a cotton/polyester blend.