How old are they? If they are about 8 or below, I's say don't worry about it and try to just make it fun for them (most important), work on enthusiasm and attitude toward archery. If you find that they are cross dominant after about 9 or so, then switch them to their dominant side. Kids can adapt much easier then adults. Really. Below is a pic of my son shooting right handed, and then a few years latter shooting left (after we found his dominant eye).