Personalized 1st birthday First Birthday T-Shirt. Our 1st birthday outfits are designed with your baby in mind, ensuring a perfect fit and maximum comfort. Whether you're looking for a sweet and girly outfit for your little princess or a dapper and handsome ensemble for your little prince, we have the perfect options for you. Let your baby shine on their big day with our charming 1st birthday outfits. 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.