Figure 2: Percentage of sperm chromatin abnormalities among three subfertile groups: Chromatin structures of sperm cells assessed by toluidine blue staining. Sperm cell heads with good chromatin structures were light blue (1); those of abnormal chromatin structure were deep blue (2) (under bright field, 20x). Percentage of sperm chromatin abnormalities in sperm cells of A. non-smokers B. tobacco smokers and C. cannabis smokers. D. A graphical representation of percentage of sperm DNA damage in three different groups of subjects. Scale bar=50 μm.