Barbara Oliver has had an intriguing relationship with her identical twin sister, Christine, over the decades. Throughout their childhoods, they were effectively treated as two versions of the one person: they were dressed in exactly the same manner and were given the same hairstyles. ¡°Our parents did everything to stress how similar we were,¡± Barbara recalls.

But when Barbara and Christine reached adolescence in the ¡®60s, the pattern changed. The girls could choose their own clothes and adopted very different fashions. ¡°I wore short skirts. Christine had longer dresses and jackets,¡± says Barbara. At the same time, differences in their personalities became more apparent. ¡°Christine is more conscientious about what she does. I am more confident. That became increasingly obvious as the years went by,¡± says Barbara.

Christine agrees. ¡°I am more self-conscious and I suffer from serious depression. There is no sign of that in Barbara. We may be identical twins but we are very different in many ways.¡±