4. Avoid environmental toxins. There's mounting evidence that numerous environmental factors have an effect onfertility. In a recent laboratory study, for instance, researchers at the University of California-San Francisco found that bisphenol A, a chemical used in rigid plastic packaging for many foods and beverages, decreased the division of uterine cells, which could potentially prevent an embryo from attaching to the uterus. Postdoctoral fellow Lusine Aghajanova presented the finding last month at the annual ASRM meeting. To be safe, don't microwave polycarbonate plastic food containers (recycling code No. 7) and avoid canned foods, since cans are often coated on the inside with BPA.
Other, more established environmental threats include lead and lead compounds, which can cause hormonal and menstrual irregularities, and radiation like X-rays, which damage rapidly dividing cells. Benzene—used to make certain rubbers, lubricants, dyes, and detergents and found in some paint, nail polish, and hair dyes—can cause women to stop having periods; exposed men may experience decreased sperm count, according to the American Fertility Association, a New York City-based nonprofit organization. Researchers are also finding that phthalates, a class of chemicals found in many cosmetics, have the potential to cause irregularities in ovulation and decrease sperm quality.
5. Maintain a good weight and healthful habits. Studies have shown that being too thin—or too heavy—can throw off women's hormone levels and suppress ovulation. Overweight men could have hormonal problems associated with low sperm count and quality.
Exercise is, of course, a key to staying on top of your reproductive game. Men, however, might be cautious about working out in tight-fitting pants like biking shorts, which can overheat the testicles. Prolonged and repeated exposure to heat can impair sperm count and movement. Smoking also damages sperm and lowers sperm counts. And, in women, smoking appears to accelerate the loss of eggs, potentially advancing the onset of menopause by several years.