I have a grandbaby coming in May and they do know that it is a boy. They have chosen yellow and green for his room and are throwing in some blue since they know he is Carson.
I think anything you would do in pastels of any color would fit very well for a "baby look". I usually go more with the red, yellow, blue, green because they used to say the brighter colors stimulate the child's intelligence. I used them with my daughter and she graduated 3rd in her high school class and Cum Laude in college. Maybe she would have been bright anyway...but a mom/grandma can help things along where they can!
Marilyn