Men's health: Test your sexual IQ

Your level of sexual desire may indeed change as you age. But, as people live longer, healthier lives, they often want to and do continue an active, fulfilling sex life well into their 70s and 80s.

Don't fall for it. No scientific research supports the use of any nonsurgical method to enlarge the penis, and no reputable medical society endorses penis-enlargement surgery performed for purely cosmetic reasons. The Food and Drug Administration has never approved any medications or devices for enlarging a penis. Because many of these techniques can damage your penis and even cause impotence, think twice before trying any of them.

Sexual activity — especially orgasm — can trigger a headache. As sexual excitement increases and peaks during orgasm, you may develop a dull ache in your head and neck. Dull, achy sex headaches are thought to be caused by tightening the head and neck muscles during sexual activity. Sex headaches associated with orgasm may be sudden and more severe as increased blood pressure causes the blood vessels in your head to dilate.

Sex headaches aren't usually a cause for concern. But it's a good idea to consult your doctor if you have headaches during sexual activity — especially if it's a new problem. Sex headaches may indicate a serious underlying problem, such as bleeding in the brain or stroke.

The quality of your diet has a lot to do with the quality of your sex life. Studies show that men who eat a diet rich in fat and cholesterol are more likely to develop erectile dysfunction (ED) — the inability to get an adequate erection for satisfactory sexual activity. Men who eat a more balanced diet that includes lean meats, nutrient-rich fruits and vegetables, whole grains and low-fat dairy products are less likely to experience ED. It's also important to limit your consumption of alcohol and caffeine, and to avoid tobacco altogether. These substances can decrease your sexual desire and rob your body of nutrients beneficial to sexual health.

Researchers have found that prolonged television viewing may be a sign of an extremely sedentary lifestyle, which, along with obesity, is associated with higher risk of ED. By increasing your physical activity and reducing your weight, you can lower your risk of complications including erectile dysfunction. Studies show that one-third of obese men with ED can regain satisfactory sexual activity after approximately two years of improving their overall health through regular exercise and weight control.

Research has shown a combination of lavender and pumpkin pie to be the number-one scent to enhance male sexual arousal. Next is the smell of doughnuts and black licorice together, with the scent of doughnuts and pumpkin pie third. These combinations of smells caused the highest increase in blood flow to the penis.

Nerves in your nose (olfactory nerves) pick up scents and send the information to your brain. Scientists have long known of the connection between smell and sexual arousal and dysfunction. Approximately 20 percent of people with a decreased sense of smell also have some sort of sexual dysfunction.

Usually you can have sex well into the third trimester of your partner's pregnancy, as long as her pregnancy is progressing normally. Your penis doesn't physically contact the fetus, which is well protected by your partner's abdomen and the amniotic fluid in her uterus. However, if certain problems exist during her pregnancy, her doctor may ask you to stop having intercourse.

But remember — there's more to a sexual relationship than intercourse. If intercourse is difficult, off-limits or not interesting to your pregnant partner, try cuddling, touching or massage. Massage can heighten sensuality and intimacy and lead comfortably to intercourse. Or it can be an enjoyable end in itself. Find the balance that works best for you.

Low testosterone can cause all of these things in a man. Around age 40, a man's body begins producing less testosterone. Testosterone is the main male hormone that maintains muscle mass and strength, fat distribution, bone mass, sperm production, sex drive, and potency. For most men, testosterone levels naturally decline but still remain within the normal range throughout their lifetimes, causing no significant problems. But about two in 10 men age 60 and older have testosterone levels below the normal range (testosterone deficiency). Some healthy men encounter changes in their sexual health as part of the aging process, possibly because of declining hormones other than testosterone. If you're concerned about low testosterone, talk to your doctor. Testosterone therapy may be a treatment option.

Even if you don't have intercourse, it's possible to get an STD if you engage in unprotected oral sex. The skin-to-skin contact and exchange of body fluids associated with oral sex make it possible for viruses or bacteria to enter your system. The best way to avoid infection is by being in a long-term, mutually monogamous relationship with an uninfected partner.

A latex condom — with or without spermicide — is your best choice for preventing STDs, such as chlamydia, gonorrhea and human immunodeficiency virus (HIV). Because latex condoms block the exchange of body fluids that might be infected, they provide better protection against STDs than do any other forms of birth control.

Polyurethane and lambskin condoms don't protect as well as latex against STDs. Though sperm can't pass through pores in these condoms, disease-causing viruses and bacteria can. Read the label on the package and make sure that the condom is latex and labeled for disease prevention.