I think branding irons are the solution to this age old problem.A friend of mine was once baby sitting for her identical twin nieces, who were about 5 at the time. She could absolutely NOT tell them apart, and they were having fun: each claiming to be the other. When one claimed to be the other, my friend said "No, you're not! Marissa is wearing blue today and you're wearing pink, so I KNOW that you're Alice!" The girls promptly disappeared into their room, then came out STARK NAKED, and full of giggles, having successfully thwarted her, again!!!![]()