This is Raglan Sweater by Debbie Bliss (link is to her Ravelry pattern page) from the book "The Baby Knits Book", which has a lot of great patterns, all of which will make you want to have a baby. I made this for Debbie Singer's son Max, who I met today and who is totally delicious. I altered the sizing specs and added bottom ribbing (knit during Warren's mock trial) so it wasn't a midriff sweater, which I think is not a good look for a baby. :)
Yarn sub: I used Bernat Berella 4 in the Seascape Ombre colorway, which I love. Despite being the same gauge as the yarn suggested in the pattern, it knit up totally different. I'm thinking I am a loose knitter, even my dishcloths are like 2 sizes too big usually.
Pattern mods: I cast on 45, for the 0-3 months size. I knit it for 5.5 inches as per the 12 month size length, but then stopped the decreases at 23 sts (the 9 month size) so the neck was wide enough. Also added two more rows of st st to the neck edge before binding off (so did 4 instead of 2 rows). IMPORTANT NOTE: If I knit this again, I need to make the body longer, about 7 inches long instead of 5.5. The ribbing I added looks okay but I would've preferred the rolled hem.
For the sleeves, I cast on 30, per the smallest size. Knit the length to 7 inches before starting the decreases. Decreased until there were 18 sts left on needle (per the 9 month size).
All the SEAMING for this little baby sweater is NUTSO. Still, it came out super cute and was well-received by Debbie. Since the body was nowhere near long enough, I picked up 88 sts around the bottom cast on edge and knit about 2 inches of 2x2 ribbing.