Objective  To investigate whether there exists communication phenomenon between twin children besides our conventional senses such as look

listen

touch

smell and taste

and explore the influence of genetic and environmental factors on this phenomenon by card-guessing tests on twins. Methods  Totally 37 pairs of twin children aged from 6 to 16

still living together were recruited in this study. Buccal mucosa samples were collected from all twins for DNA extraction and zygosity identification test. Twins were divided into monozygotic (MZ) twin group and dizygotic (DZ) twin group according to their zygotic identity. Card-guessing tests were performed to compare the number of correct hits in twins between the MZ and DZ. The number of correct hits in guessing the cards in twins was compared with those expected by chance. Results  The number of correct hits in twins was greater than those expected by chance

and the number of correct hits in MZ twins was greater than those in DZ twins

but there was no significant difference. Conclusion  There may exist the communication phenomenon not through conventional senses. The presence of this phenomenon may be contri-buted to similar genetic basis and living in the same environment

and the two of which have no difference.