POSTED: 7:34 am EDT October 22, 2004 PHILADELPHIA -- Two new studies warn of the effect your weight may have on your ability to reproduce. Danish researchers found that overweight men are more likely to have poor sperm quality. They also warn that being too thin also seems to cause problems. The researchers considered factors like sperm counts and concentration, along with hormone levels and weight. There's also further evidence that weight can affect the reproductive health of women. Researchers at Beth Israel Deaconness Medical Center in Boston have confirmed that obese women are less likely to become pregnant even if they've been implanted with embryos fertilized outside the womb. The women's study was presented this week at a medical conference. The study on sperm appears in the medical journal Fertility and Sterility.