Latest psychoanalytical research, based on the integration of the genetic-reconstructive method and the observative-developmental one, points out that twinship presents specific difficulties in the structuring of Self. The unfavourable feature in the structuring of Self in twins is the sharing of the mother from the very beginning of in-trauterine cohabitation passing to the relative deficiency of primary maternal care. The clinical cases of two adult DZ twins under psychoanalytical – psychotherapy treatment are herein reported to emphasize: the defective formation of a sense of personal identity; the high recurrence of cross-projective identifications; and, the tendency to assume complementary roles and re-create bonds and relationships similar to the ones experienced with the cotwin. Within the therapeutic relationship, the following features come to light: the unconsciously fantasized presence of the other twin; the strong feelings of self depreciation, inability and angry emptiness. These feelings seem to enhance an adhesive transference, presenting difficulties in separating, strong ambivalence and fantasies of a continuous analysis with the analyst-twin. In the cases we report, the twin pair relationship with its dynamics, bound to the incomplete or defective structuring of Self, represents the essence of the relationship between the twin and the object.

Twins and twin research are providing fresh insights into the roots of political behavior. This topic is approached from dual perspectives: why some individuals choose to become politicians, and why individuals vary in their political attitudes and interests. Reviews of timely twin studies in the areas of pair-bonding, facial expressivity and education follow. Finally, some extraordinary events in the lives of twins and their families are revealed.

The increased frequency of interracial marriage is a likely source of unusual-looking dizygotic (DZ) twins. Some members of DZ twin pairs born to mixed-race couples inherit very different physical features from their parents. This raises several questions, such as: Will researchers wish to include such twins in their ongoing studies? Next, new twin research concerned with congenital anomalies, mirror-image effects in conjoined twins and older mothers of twins will be reviewed. New statistics on twinning rates in Massachusetts will also be summarized, followed by a tribute to the late medical geneticist Dr. Victor A. McKusick.

White male twins from the NAS-NRC twin sample, who were born in the U.S. between 1917 and 1927 and served in the military, are used to estimate variability in hazard functions for those twins who died during the period 1974-1990. Roughly the same number of MZ and DZ twins died during this period, but their death rates are similar. DZ twins exhibit greater within-pair variation. Using hazard and other analyses, the only statistically significant variables are found to be being a DZ twin (in level equations), date of birth, and, sometimes, wife's religious preference. Variables not significant for level or within-pair equations, include own religion, parental education, working overtime frequently, and number of children. The greater variation in life expectancy of DZ twins is hardly surprising and may say something about the lack of comparability in phenotype variance of DZ twins, which in turn may be worrying.