I find sizing can be confusing when knitting Baby items The Craft Yarn Council Site has a size chart that is good for Baby sweater sizing and Bev’s Country Cottage has an abundance of information and patterns. I have found Crochet Rochelle has a very useful hand size chart.
My all time favorite baby sweater is the “5 hour Baby Sweater” it is so versatile. I got my original copy of the pattern from Woolworks and it can be made for a boy or a girl . Over the years I have made it into a set by adding a hat, mittens and booties, I have downsized it for a Preemie version and up-sized it for a Toddler version. I have made the Fiber Gypsy’s hooded version and Ó Gail Bable’s boy version has been well received. Not forgetting the variety of options on Bev’s Country Cottage site.