Think "fertility problem," and most people assume there's something wrong with the female half of the conception equation. In fact, when couples are having trouble making a baby, what's known as "male factor" is responsible an estimated 40 percent of the time. Here's what a guy can do—and what he should avoid doing—to maximize his chances of making plenty of hardy, healthy, fast-swimming sperm.
Eat Oranges, Not Cheetos: Eating fruits, vegetables, whole grains and low-fat protein helps prevent a man from coming up short on the nutrients necessary for making top-notch sperm; vitamins C and E, zinc and folic acid are particularly important. Over-the-counter supplements such as FertilAid for Men and FertilityBlend for Men, which contain sperm-friendly vitamins and minerals, are safe to take and may help, but there's no proof they boost pregnancy rates.
Review His Medications: Certain drugs, including steroids and those that treat high blood pressure, ulcers, hair loss and depression, may impair a man's ability to father a child. Every medication he takes—over-the-counter as well as prescription—should be checked with his doctor or pharmacist for possible effects on fertility.
Kick Some Butts: Smoking cigarettes creates free radicals that cause cell damage, lowering sperm count and diminishing sperm quality. Dad's smoking habit may also increase his future children's chances of developing leukemia and lymphoma.
Moderate the Mountain Biking: If a man logs a lot of miles mountain biking, he can incur testicular damage that reduces his ability to father a child. Stopping frequently to rest, wearing padded bike shorts and using a padded seat reduce the chance of problems, even if he's a road biker.
Get a Move On: If he's over 30, you may want to get started on the baby-making process. One study of healthy nonsmokers found that 50-year-old men made 20 percent less sperm than 30-year-olds. The researchers estimate that sperm volume and motility (movement) decrease by about 5 percent each year after age 30.