Sperm smarts: Optimizing fertility

In order to father a child, you need lots of high-quality, fast-moving sperm. Sperm are made in the testicles, which are suspended in the scrotum outside your body. This anatomical arrangement keeps the testicles a few degrees cooler than your normal internal body temperature, which is necessary for healthy sperm production.

Testicles constantly produce sperm. Fluids from the prostate gland and seminal vesicles mix with the sperm to form semen, which is stored in the seminal vesicles. Each sperm has a long tail that propels it forward. Of the millions of sperm in the ejaculated semen, about 200 may reach the egg in a woman's fallopian tube but only one may fertilize it.

Male reproductive system

Male reproductive system

The male reproductive system makes, stores and moves sperm. Testicles produce sperm. Fluid from the seminal vesicles and prostate gland combine with sperm to make semen. The penis ejaculates semen during sexual intercourse.

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How to have high-quality sperm

It takes only one sperm cell to fertilize an egg. With 500 million sperm vying for the opportunity, you'd think each act of intercourse between you and your partner would have excellent odds of resulting in conception. In fact, it's never a sure thing, even if you're both healthy and your timing is right — that is, you have sex within three days (72 hours) of when the egg enters the fallopian tube (ovulation). Here's what you can do to increase your chance of contributing enough hardy, energetic sperm to get the job done.

• Consider a multivitamin. If your eating habits are irregular, a daily multivitamin usually provides adequate intake of selenium, zinc and folic acid, trace nutrients that are important for optimal sperm production and function. Sperm are particularly susceptible to oxidants, unstable oxygen molecules that damage cell membranes. A multivitamin also usually contains antioxidant vitamins such as C and E, which may help protect sperm from this damage.
• Reduce stress. Excessive or prolonged stress may interfere with certain hormones needed to produce sperm. A long-term fertility problem may be a stressor in itself, directly or indirectly contributing to infertility by interfering with hormones or impairing sexual function.
• Exercise regularly. Physical activity is good for your general and reproductive health. Contrary to what you may have heard, even strenuous exercise such as marathon running probably won't adversely affect your fertility. Just don't overtrain.
• Watch your weight. Too much or too little body fat may disrupt production of reproductive hormones, which can reduce your sperm count and increase your percentage of abnormal sperm. You're most likely to produce lots of high-quality sperm if you achieve and maintain a normal body mass index (BMI) between 20 and 25.

Caution: Hazardous to sperm

Even under the best circumstances, only 50 percent to 70 percent of a man's sperm are viable enough to fertilize an egg. This suggests that sperm may be especially vulnerable to environmental assaults, such as exposure to excessive heat or toxic chemicals. To protect your fertility:

• Watch out for toxins. Many workplace and household chemicals and substances may reduce sperm quantity and quality. These include hydrocarbons such as ethylbenzene, benzene, toluene and xylene, found in such products as asphalt, crude oil and roofing tar; heavy metals such as lead, cadmium and mercury, used in some batteries, pigments and plastics; and aromatic solvents used in paint, varnish, stain, glue and metal degreasers. Some pesticides and herbicides have estrogen-like effects that disrupt sperm production. Protective clothing, proper ventilation and face masks can reduce the risk of absorbing such toxins through your skin, mucous membranes and lungs.
• Avoid tobacco and limit alcohol. Smoking may increase the risk of infertility and erectile dysfunction in men. The sperm of men who smoke one to two packs of cigarettes a day may be misshapen and may move more slowly than those of nonsmokers. Smokeless tobacco also adversely affects sperm quantity and quality. Similarly, heavy drinking may lower testosterone levels and reduce the quality and quantity of sperm. Limit alcohol to no more than one or two drinks a day. The combination of tobacco and alcohol is particularly harmful to sperm. Men who drink and smoke have significantly lower sperm counts and motility than do men with either habit alone.
• Shun recreational drugs. Marijuana can decrease sperm density and motility and increase the number of abnormal sperm. Cocaine and opiates can contribute to erectile dysfunction, and amphetamines can decrease sex drive.
• Skip the sauna. To maximize the quality and quantity of your sperm, avoid saunas, steam rooms, hot tubs and whirlpools. Spending more than 30 minutes at a time in water heated to 102 degrees Fahrenheit (40 degrees Celsius) or more may lower your sperm count.
• Head for the shower. Long, hot baths reduce the number and vitality of sperm just as much as hot tubs and saunas do. Take showers instead.
• Get off your duff. Prolonged sitting at work, at home or in your car may raise scrotal temperature and impair sperm production. If you have a sedentary job, take frequent breaks at work and choose leisure-time activities that get you out of the driver's seat and off the couch.
• Avoid hormone havoc. Think testosterone supplements will work in your favor? No way. Excess testosterone actually decreases fertility. Anabolic steroids, usually taken illegally to increase muscle strength and growth, can shrink the testicles and drastically reduce fertility. Anti-androgens used to treat prostate enlargement and cancer also interfere with sperm production.
• Review your medications. Many prescription medications may temporarily reduce your fertility. If you take medication to control a chronic condition such as high blood pressure, inflammatory bowel disease or gout, or to suppress your immune reaction to a transplanted organ, ask your doctor how your treatment may affect sperm development. Also, avoid cimetidine (Tagamet, others), a stomach-acid-suppressing drug available without a prescription. Instead, use ranitidine (Zantac, others), famotidine (Pepcid, others) or nizatidine (Axid), which decrease stomach acid without affecting fertility. If any other medication you're taking may decrease your fertility, ask your doctor whether a substitute drug is available. A few medications, including several common chemotherapy agents, may cause permanent infertility. If you'll be undergoing chemotherapy, talk with your doctor about saving and freezing your sperm (semen cryopreservation).

Separating fact from fiction

A number of sperm-related urban legends have made the rounds in recent years, including groundless rumors that menthol cigarettes and certain soft drinks can make men sterile. Here are a few others with no basis in fact — and some that turn out to be true.

• Tight shorts reduce sperm count. Not true. Despite anecdotal reports that boxer shorts are better than briefs, researchers have found no scientific proof that briefs, athletic supporters or tight trousers adversely affect fertility, even if worn daily.
• Coffee jangles more than nerves. Not true. Caffeine consumption has no effect on male fertility.
• Bicycling sabotages the system. True. Sitting on a hard, narrow bicycle saddle for more than 30 minutes at a time — especially if you also wear tight-fitting bicycle shorts — may raise your scrotal temperature and affect sperm production. In addition, the associated bouncing and jarring may cause genital numbness and damage delicate nerves and arteries. To possibly reduce such risks, point the saddle slightly downward, use a wider saddle, wear padded bicycle shorts and take frequent rests while biking.
• The calendar also matters to men. True. Since cooler temperatures are associated with increased sperm production, sperm counts are higher in the winter and lower in the summer. They're also higher in the morning than at other times of day.

Adopting healthy lifestyle practices to preserve your fertility — and avoiding things that can damage it — may improve your and your partner's chances of conceiving a child. But you still may not become a father on your first — or even 51st — try. If you and your partner haven't achieved a pregnancy after a year of unprotected intercourse, see your doctor and get a semen analysis. Forty percent of infertility can be traced to men alone, 40 percent to women alone and 20 percent to both. A fertility specialist can identify the cause of the problem and provide treatments that may help place you and your partner on the road to parenthood.