The good news is that, if the survivor is aware of what happened, the trauma can be processed and overcome, sometimes quite rapidly. Twins from whom information about a twin's death is hidden or who are not allowed to express their feelings about the loss suffer most. The parents of VTP survivors may suffer confusion and unresolved feelings of great loss if the VTP is not carefully explained to them and allowances made for the grief a parent feels upon losing an offspring, whatever the circumstances. Occasionally the remnants of a twin are found in the placenta or, more rarely, in a teratoma tumor, which may contain hair, bone, teeth or other fetal tissue, and which may occur inside or outside the surviving twin or in the mother. Current studies are confirming a previously suspected link between cerebral palsy and the twinning process.
Twins are also more likely to be left-handed than singletons.
Fraternal twins tend to run in families. All of these are important reasons a surviving twin should be advised of his or her twinship. A curious phenomenon of the twinning process is the chimera, an individual with different cell populations derived from more than one fertilized egg. Of course, there is no way to determine whether identical twins have merged, since their genes and blood types are the same. He looked the same, but there was something wrong.