Model knit in Evolution DK from Chameleon Colorworks
From the pattern:
Tradition (together with much folk lore) would have boys' garments button from the left and girls' garments button from the right. You may not know the gender of the wee-one for whom you are knitting this gift. That leaves you with three choices: 1) Wait to knit on the bands until the baby is born; 2) knit both bands with buttonholes and sew on the buttons after the baby is born, over the unused buttonholes; or 3) pick a side for the buttonholes in the secure knowledge that the baby will not care!