Smoking

In addition to harming your overall health and raising your risk for lung, colon, and pancreatic cancer, smoking can decrease your ability to conceive. Smoking causes ovarian follicles to mature more quickly, increasing the risk of infertility and bringing on early menopause. Therefore, avoid smoking at all costs.

Men should also stop the habit. While the effects of smoking aren't as obvious in men, research indicates that the habit may harm sperm's structure and function, and the level of the harm may be linked with the amount smoked. However, the good news for men is that they constantly produce sperm because it is a dynamic process. If your partner gives up smoking right away, the harm that smoking has done could be repaired in three months when a new sample of sperm matures and reaches the ejaculate.