Originally Posted by PaperPrincess

What Holice said. Bias tape is cut on the BIAS so that it will go around curves. Seam binding, ribbon etc. is on the straight of grain. If the curve is very gentle it may work, but with kid's clothes I'm guessing that the curve is pretty sharp on the arm holes & neckline. If you can't find premade bias tape, I'd get a half yard of a coordinating solid fabric & just cut some yourself. Twill tape comes in several weights and the lightest one is very loosely woven, it has some give so that might work.