Fertility specialists can now magnify human sperm by 7300 times its normal size and found that patients in a pilot program had an average of 30 per cent DNA-damaged sperm. "DNA damage can be genetic or caused by environmental or lifestyle factors including smoking, obesity and diabetes. Exposure to toxins, including chemotherapy, can also damage the chromatin, as can some genital tract infections." "The technique is being used to help men whose partners have experienced repeated infertility or miscarriages due to DNA damage to sperm or significant morphology problems, such as sperm with oddly shaped or multiple heads."