If you're having problems conceiving, you should be aware of some of the possible causes of infertility in men. Some problems can be treated by your doctor to help you achieve conception. DES (D-E-S), a synthetic estrogen used in the 50s and 60s to prevent miscarriage, can cause low sperm counts and motility as well as small penis size or abnormal testicles. If your mother took this drug, you're reproductive ability might be affected. Hormonal balance and impotence are other sources of problems with infertility. Low sperm count or motility as well as impotence can make it almost impossible to unite sperm and egg, but doctors can advise you on how to increase both levels. Prior surgery, including vasectomy reversal or chemotherapy can also cause problems with male reproduction. While some infertility causes need medical attention, others can be taken care of by altering your lifestyle. Changing your underwear, for example, can help sperm production. Loose boxers help keep temperatures lower for healthy sperm. Avoiding hot water, bicycle seats, and prolonged periods of sitting can also be helpful.