Fascination with the twin bond has gripped cultures all over the world for millennia (Bryan, 1983). Although only approximately 3% of the total general population are twins, those who are twins have imbued twin relationships with expectations of extreme closeness, magical understanding, private languages, individual's fantasies of having another self(Bank & Kahn, 1982; Center for Disease Control [CDC], 2000). In 2000, the number of surviving individuals resulting from multiple births was 125 million worldwide. Equal fascination with the severing of this mystically strong bond seems like a foregone conclusion. Yet, strangely, a paucity of research has been conducted to investigate how twins cope with the death of a co-twin. Because the number of multiple births continues to increase, due to the use of fertility drugs and women waiting until later life to give birth, the likelihood of counselors encountering surviving members of a twin loss is growing. Women who wait until later life to conceive are at higher risk for conceiving multiple fetuses due to the irregularity of ovulation (i.e., as women age, the chances of both ovaries developing a follicle and both releasing these follicles during ovulation increases) as well as the increased need for fertility drugs to assist in conception. Counselors working with the bereaved surviving twin (or other surviving siblings in higher order births) need to understand the unique aspects of the twin relationship and resulting complicating factors for the grief process. Therefore, the focus of this article will be on the unique bereavement experience of the "twinless twin," the ways in which patterns of identity development affect the severity and nature of this grief, and implications for counseling the survivor. Overview Identical twins, more scientifically referred to as monozygotic (MZ) twins, are formed when one fertilized egg, or zygote, splits into two eggs, leading to the formation of two babies who share 100% of their genetic material (Bryan, 1983). Fraternal, or dizygotic (DZ) twins result when two separate eggs are released and fertilized by two separate sperm. This process results in two babies who share as much genetic material as singleton siblings, which is only about 50% of the genetic material (Segal & Ream, 1998). In the United States, 3% of all live births result in twins (CDC, 2000), making 6% of all babies who are born alive, twins. Throughout the world, rates of MZ twins are roughly the same (about 3 to 4 per 1,000 births), whereas rates of DZ twins are highest in Nigeria and lowest in Japan (Bryan, 1983). It is well known that MZ twins occur randomly, whereas DZ twins seem to run in families (Bryan, 1983; CDC, 2000), although some research suggests that these patterns may be more complicated than were initially thought (Segreti, Winter, & Nance, 1978). Stories, stereotypes, legends, and fantasies surround the mystery of twinship, but the general public's understanding of twins often ends with this fascination (Noble, 1983). Being a twin, and experiencing what Schave and Ciriello (1983) termed the twinning bond, carries both advantages and liabilities. For example, the intense closeness that comes to play a central role in the lives of twins (Wilson, 1995) can provide some protection against loneliness, easing the pains of adolescence (Pector, 2002) and, according to one study, serving as a deterrent to suicidal behaviors. A further example to illustrate the potential negative impact of the twin bond could be that research finds that the bond can also impair social relationships (Pector, 2002), increase the risk of academic delays due to circumstances such as "twin language" slowing development of appropriate communication skills (Pector, 2001, 2002), lead to difficulties with inequality (Woodward, 1988, 1998), and result in delayed individuation (Engel, 1975; Schave & Ciriello, 1983). Perhaps the most interesting consequence of the twin bond, and the most relevant to the issue of twin bereavement, is the fact that twins tend to form their identities along patterns distinct from those of singletons. …