The problem I am encountering when trying to knit newborn hats is that you need to knit "in the round" to prevent seam in the back of the hat. This requires using three double pointed needles or two sets of circular needles. Even a short circular needle won't work because of the decreased number of stitches at the crown of the hat.
Probably should go with 16 inch plastic circular needles per a local knitting instructor.