Studies at the University of Maryland show that 90 percent of men's infertility problems are caused by sperm problems, such as low sperm count, low quality, or both. In addition, the anatomy of the body, the lack of balance in hormones and genetic problems are other reasons. The European Society of Urology also mentions male infertility, varicoceles, or enlargement of one of the testes, testicular obstruction, infectious diseases, or prostate problems. The global population growth shows that one in eight couples suffers from infertility, about 12% of all couples. World Health Organization statistics also show that 20 percent of infertility in the world is related to men, 38 percent are women, 27 percent have both problems. Infertile couples face emotional disturbances, and men face a more intense emotional response when faced with this problem. Like women, gentlemen experience a decrease in confidence and lack of feelings, and their percentage is higher than that of women. "Generally fertility in men is tied to the concept of ability and power, and many infertile men feel less masculine," said Dr. William Petok.