Ice breakers can be used to create familiarity within the group and ease everyone into the group process. The desired end result is a more open discussion forum and pleasing environment within the group in which the group process can continue.
1 To form identical or monozygotic twins, one fertilised egg (ovum) splits and develops into two babies with exactly the same genetic information.  To form fraternal or dizygotic twins, two eggs (ova) are fertilised by two sperm and produce two genetically unique children.
So when one egg is fertilized by single sperm then identical twins or mono zygotic are born and they are always of same sex. But when two different eggs are fertilized by two different sperms then fraternal twins are born. In fraternal twins sex of both twin are irrespective of each other .