The investigators hope to learn if Letrozole is effective and safe in improving severe male
infertility by increasing testosterone, decreasing oestradiol and stimulating sperm
production thereby improving sperm motility (movement) and concentration. The study is being
conducted because Letrozole is not yet proven to be a standard treatment in subjects with
absent or very low sperm counts. The investigators are hoping to determine whether Letrozole
is equal or superior to no treatment.