So Relative! 2-Pack SET Big Sister/Little Sister Kids T-Shirt & Baby Bodysuit 2-Piece set: One (1) Youth Short Sleeve T-Shirt (choose size) & One (1) Bodysuit (choose size) included. Approximate bodysuit sizing: Newborn (up to 12 pounds), 6 Months (12-18 pounds), 12 Months (18-25 pounds), 18 Months (25-30 pounds). Youth XS (2-4); Youth Small (6-8); Youth Medium (10-12); Youth Large (14-16); Youth XL (18-20). Both the T-Shirt and bodysuit are 100% cotton. Great gift for expectant moms/dads!