I was twenty or more years old before I realized that I was cross-dominant. Right handed and left eye dominate/master. It was a struggle but I have learned to adapt, and luckily since my heart doctor will not approve me shooting my shotgun from my left shoulder due to the position of my pacemaker. I think the red dot sight may have solved the problem for most. I plan too experiment with my two year old grandson to see if he will bring a paper towel tube to his dominant eye instinctively while attempting look at an object. Of course, I will have to live a bit longer to be able to determine for certain his dominant/master eye.