Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-nick end labeling or the TUNEL assay is an important technique in the assessment of DNA damage. Semen samples are routinely assessed microscopically to assess their fertilization ability. In addition to routine semen analysis, the use of the TUNEL assay can provide information on the level of DNA damage present within a sample. This chapter provides a practical walk-through guide aimed at directing a researcher or a clinical facility interested in setting up and using TUNEL and flow cytometry or fluorescence microscopy for sperm DNA analysis.
