Described herein is a method for detecting structural and numerical chromosome abnormalities in sperm cells. This invention can also be used to detect chromosome abnormalities resulting from exposure to factors such as chemicals, other materials, radiation and environmental conditions. This invention will allow for the wide spread screening of many different types of factors such as chemical, other materials, radiation and environmental conditions to determine whether they have the chromosome abnormality generating effects
 The United States Government has rights in this invention pursuant to Contract No. W-7405-ENG-48 between the United States Department of Energy and the University of California for the operation of Lawrence Livermore National Laboratory.