As an identical twin, I find the Doublemint mystique of Mary- Kate and Ashley Olsen's shared birth a mixed blessing that few "singletons" would wish on themselves ["Power of Two," Style, June 2]. In an era in which the expression of individuality in childhood is recognized as key to development of character and self-worth, twins are rewarded from the start for their every nuance of shared style and behavior, and they are discouraged when they display normal differences. How many singletons would want to go through school wearing the same clothes and hairstyles as their siblings, share the same friends and continually hear, "I can never figure out which one of you is which!"

Being a twin did have the occasional advantage: My brother and I illicitly took a course for one another in school -- something that is oddly expected of twins -- but I was not amused when I got him an A and he got me a C. We could swap the hard-to-find shoes for our narrow, size 13 feet, with an almost perfect fit guaranteed.

But even strangers felt free to converse with us about swapping our organs in the event of need. I still remember the reprimand I got from a high school teacher when I said I had no intention of sharing my kidneys -- as if being a spare-parts model was understood to be part of my condition.

My brother and I got a divorce from twindom 30 years ago, and we are no longer seen as a cute aberration. The Olsen twins -- who are not identical, but fraternal -- are showing normal signs of separation and self-expression for young women their age. But it's unlikely that fame and twin obsession will fully allow them to become individuals without criticizing them for wanting to do so.