Chromosomal translocation, or simply translocation in genetics, is the absence of a proper set of chromosomes in a human cell (Usually, we have 46 chromosomes in most cells. We inherit our chromosomes from our parents, 23 from our mother and 23 from our father, so we have two sets of 23 chromosomes or 23 pairs). A translocation means that there is an unusual arrangement of the chromosomes. This can happen because: a) a change has arisen during the making of the egg or the sperm or around the time of conception; b) an altered chromosome arrangement has been inherited from either the mother or the father. There are two main types of translocation: a reciprocal translocation and a Robertsonian translocation. A reciprocal translocation occurs when two fragments break off from two different chromosomes and swap places. A Robertsonian translocation occurs when one chromosome becomes attached to another.