ABSTRACT
Siblings have an important place in our inner world. Twins are siblings of a distinctive kind and, while their relationship is at least as important as those of other siblings, the twin relationship also poses problems for the developing twins, difficulties that are unique to twins. The idealization of sameness obliterates difference and the value of difference, and denies the need for an individual sense of self. Perhaps the need for sameness in these twin sisters was exacerbated by the splitting that seemed to define each twin. Twins are usually divided into two distinct groupings: monozygous or same-egg twins, and dizygous or different-egg twins. Thus, monozygous twins originate from one egg that splits at a very early stage into two embryos. Dizygous twins are the result of the simultaneous fertilization of two eggs.
