Human beings are unique among animals in having the capacity for sexual desire even when the female is not fertile and in retaining desire into old age, long after conception has ceased to be possible. The explanation may be that sex helps maintain partnerships. Regular sex also seems to improve cardiovascular fitness and prolong life. People who are involved in stable sexual relationships live longer than those without sexual partners.

A satisfying sexual relationship is an important part of life but not always easy to achieve, and sexual contact may be risky. In particular, casual sex and sex with multiple partners carry the risks of unwanted pregnancy and sexually transmitted diseases (STDs).

The first article in the section covers the basic elements of a healthy sexual relationship. The article on safe sex discusses ways of reducing your risk of exposure to sexually transmitted diseases. The final article provides an overview of the advantages and disadvantages of different forms of contraception. Education about sex, pregnancy, and STDs is particularly important for teenagers, who often fail to make use of contraceptives and ignore advice about safe sex. In the US, this has resulted in one of the highest rates of teenage pregnancy in the world.

Specific sexual problems and the symptoms and treatment of sexually transmitted diseases are discussed in other sections of the book (see Sexual problems and Sexually transmitted diseases), as are possible problems in conceiving (see Infertility).

Enjoying intimacy When two partners are establishing an intimate, sexual relationship, it is important for them to trust each other.

Sexual relationships
The physical and emotional elements of satisfying sexual relationships.

The physical maturity necessary for a sexual relationship is signaled by the onset of puberty, when the individual’s body makes the transition from childhood to adulthood. The development of emotional maturity frequently takes much longer, and early sexual encounters, although sometimes exciting, may just as often be disappointing or cause anxiety. With age and experience, most people become better able to establish and fully enjoy sexual relationships.

A HEALTHY RELATIONSHIP
What constitutes a healthy sexual relationship varies widely from person to person. Sexual fulfillment depends on a blend of physical and psychological factors, and what is right for one couple may not suit another. You and your partner should both be happy with the frequency of sexual activity, and you should be able to discuss which sexual activities you find pleasant and which you find unappealing.

Anyone in a sexual relationship should be aware of the risks posed by sexually transmitted diseases (STDs) and understand how to minimize the risk of exposure to them (see Safe sex). To avoid an unwanted pregnancy, you should be familiar with the options for contraception, including emergency contraception. It is important that children approaching puberty are given education about STDs, safe sex, and contraception. Most schools provide sex-education programs.

POTENTIAL PROBLEMS
It is normal to experience fluctuations in sex drive or occasional temporary loss of sexual desire, lack of sexual response, or inability to perform sexually. However, if sexual problems persist, they may be distressing and cause you anxiety, which further impairs your ability to enjoy sexual activity, and this creates a vicious cycle.

Sexual problems may have a number of causes. Emotional difficulties in your current relationship will affect your sex life. External stress will also affect a relationship and may lead to problems. For example, ongoing problems at work or financial difficulties may cause anxiety, irritability, or lack of sleep, all of which may decrease your desire for sex. Past upsets of an emotional nature, such as the breakup of a former relationship, can affect your current situation even when the problem seems to have disappeared.

Decrease in sex drive or impaired sexual function may also be the result of complications of certain long-term physical conditions, such as diabetes mellitus; disabilities that cause pain and restrict movement; convalescence from surgery or severe illness; and the use of alcohol, recreational drugs, and certain medications.

By David R. Goldmann, EDITOR-IN-CHIEF and David A. Horowitz, ASSOCIATE EDITOR

David R. Goldmann, MD, FACP is Vice President and Editor-in-Chief of the Physician’s Information and Education Resource at the American College of Physicians, Associate Editor of the Annals of Internal Medicine, and Associate Editor of the Annals of Internal Medicine, and Associate Professor of Medicine at the Hospital of the University of Pennsylvania.

David A. Horowitz, MD is Medical Director of the Department of Clinical Effectiveness and Quality Improvement, University of Pennsylvania Health System, and Assistant Professor of Medicine at the Hospital of the University of Pennsylvania.

Complete Home Medical Guide (Print version published in association with the American College of Physicians); 2003, p67-71, 5p, 2 diagrams, 1 graph, 13c