When choosing a knit for a new baby, one should choose something functional. It should be knit a couple sizes bigger than the baby to get good use out of it. Afterall, when spending x number of hours knitting away at something, you'd hope that little wee one could wear it more than once.
It should be fairly straightfoward to put on the little joy to appease the jittery hands of new parents. Babies hate having things put over their head, you're guaranteed a red faced scream every time. It should be neutral in colour, so that the next generation of babies of unknown genders can enjoy this beautiful family heirloom.
OR, you can throw out all that logic out the proverbial window and cast on for the most adorable little NEWBORN sized, BLUE sleeper, that fits OVER the head, for the most precious baby boy due to arrive any minute. Precious trumps function. Always.