KIDS LOVE BRIGHTS! KIDS LOVE RED! REGARDLESS OF BOY OR GIRL
i would find some wonderful primary colors....good strong bright red, blue yellow, green, orange and purple...and some LIME for good measure...
i made a little guy a thomas the train quilt a few years ago- it had a fire=engine red background...with bright royal blues- blacks- yellow...he loves it! his mom complains he has really outgrown it- every time she tries to pack it away for years from now he finds it and gets it back out- he was 4 when i made it= he's almost 12 now---and he does not care if Thomas the train is no longer of much interest- that quilt remains an important part of his life!