20.2 The Sexual-Reproductive System

As you just read, although senescence affects every body part, 60-year-olds can usually accomplish almost everything 30-year-olds can, albeit more slowly and carefully. However, one critical activity becomes virtually impossible for women and difficult for men as they approach age 50—reproduction.

Contraception

The aging of the sexual-reproductive system is universal. Whether or not that matters to an individual depends on historical context (including medical advances) and local values; the most obvious example is birth control. Without it, many women avoided sex because they did not want pregnancy. Now contraception has transformed female sexuality, affecting men as well.

Local values shape contraceptive patterns. For example, couples in India rely on female sterilization to control family size but virtually never use male sterilization (Sunita & Rathnamala, 2013). In the United States almost two-thirds of sexually active women over age 35 are sterilized, with an overall female-to-male ratio of about 2:1. That ratio varies by ethnicity: Among African Americans and Latinos, far more women than men (about 6:1) are sterilized (U.S. Center for Health Statistics, 2012).

The most popular contraception for younger women in the United States and France is the birth control pill, but the pill is almost never used in Japan except to regulate menstruation (Matsumoto et al., 2011). No contraception is available in some poor nations, even though unwanted or poorly spaced births are a major cause of mortality (Cleland et al., 2012).

With no contraception allowed in Bangladesh, couples use early abortion (without calling it abortion) to control family size (Gipson & Hindin, 2008). Worldwide, abortion is illegal in some nations and readily available in others. The United States is between these extremes in practice but politically polarized, as is evident in state-by-state differences in abortion access.

Such marked variation in preferred ways to prevent unwanted births is an example of the disconnect between human biology and psychology. This disconnect is also dramatic in sexual arousal, orgasm, fertility, and menopause—all biological, but the effects, and even the occurrence, are strongly influenced by the mind (Pfaus et al., 2014). As many say: “The most important human sexual organ is between the…ears.”

Sexual Responsiveness

Sexual arousal occurs more slowly with age, and orgasm takes longer. For some couples, these slowdowns are counterbalanced by reduced anxiety and better communication, as partners become more familiar with their own bodies and those of their mates. Distress at slower responsiveness seems less connected to physiological aging than to troubled interpersonal relationships and unrealistic fears and expectations (Burri & Spector, 2011; LaMater, 2012).

Most people are sexually active throughout adulthood. One study found that, on average, sexual intercourse (the most studied expression of sexual activity) stopped at age 60 for women and 65 for men. That was the average, but many stop before 60 and others are sexually active in their 80s (Lindau & Gavrilova, 2010). A study of German adults, ages 18 to 93, confirmed that sexual desire and activity are reduced with age for both sexes. Partner availability is key. In addition, unemployment reduced male desire and past sexual trauma (abuse, rape) affected female desire (Beutel et al., 2008).

Some adults say that sexual responsiveness may improve with age. Could that be? Is faster not always better? At least there is no proof that sexual responsiveness worsens; arousal and orgasm can continue throughout life.

According to a study of Chicago couples conducted in the early 1990s, most adults of all ages enjoyed “very high levels of emotional satisfaction and physical pleasure from sex within their relationships” (Laumann & Michael, 2000, p. 250). That study found that most men and women reported that they were “extremely satisfied” with sex if they were in a committed, monogamous partnership—a circumstance more likely after age 30 (Laumann & Michael, 2000).

Improved sexuality with age may be a cohort change, not a physiological one. For some people, especially those born before 1950, sex was considered shameful and dirty when they reached puberty. Then, as contraception improved and mores changed, sex was seen as fulfilling and positive. As attitudes changed, sex became more satisfying.

His Arm Around Her Whether in formal wear (the Akha pair in Thailand) or casual North American clothes, at every adult age couples delight in being close to each other, physically and emotionally.

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Is it still true that some adolescents and younger adults are anxious and confused about sexuality and terrified of accidental pregnancy? In adulthood, do people still become more secure in their sexuality and more confident of family planning? If the answer to both questions is yes, then sexual responsiveness would become better as adulthood progressed because fear and guilt would be diminished and slower climax would allow longer and more varied lovemaking.

A study of women aged 40 and older found, as expected, that sexual activity decreased each decade but that satisfaction did not (Trompeter et al., 2012). That study may not reflect a universal pattern, since participants were mostly upper-middle-class European American women, and the data was collected via questionnaires. For political reasons a valid, longitudinal, representative, large-scale study of sexual responsiveness has not been done.

It is likely, however, that cohort changes are improving sexual responsiveness. Even a few decades ago, sex was furtive or forbidden for adults who were gay, lesbian, divorced, or never married. That is less true today, at least in the United States, where adults in any of those four groups are more accepted. Adults may experience increased sexual responsiveness with age.

Fertility

Although sexual activity is understudied, considerable research has been done on infertility, often defined as being unable to conceive after trying for at least a year, although the definition varies from nation to nation (Gurunath et al., 2011; Hayden & Hallstein, 2010). For couples who want children but have none, aging adds to their regret; for couples who prefer to remain childless, age brings relief.

Infertility rises when medical care is scarce (Gurunath et al., 2011) and thus varies from nation to nation. In the United States, about 12 percent of all adult couples are infertile, partly because many postpone childbearing long past adolescence. Another group (perhaps 10 percent of all adult women in Germany, the United Kingdom, and the United States—and far fewer in most other nations) chooses to avoid motherhood (Basten, 2009).

If North American couples in their 40s try to conceive, about half fail and the other half risk various complications. Of course, risk is not reality: In 2011 in the United States, 116,000 babies were born to women age 40 and older, the only age group in which the birth rate is rising (Hamilton et al., 2012). One-fourth of these were first births. Although complications increase with age, almost all babies born to older women become healthy children.

As explained in Chapter 17, fertility peaks in late adolescence. From a biological (not psychosocial) perspective, women should try to conceive before age 25 and men before age 30. If they are unsuccessful, medical intervention usually helps if they are still relatively young.

When couples are infertile, the cause is in the man about one-third of the time, in the woman another third, and a mystery in the final third. Now some specifics.

A common reason for male infertility is a low sperm count. Conception is most likely if a man ejaculates more than 20 million sperm per milliliter of semen, two-thirds of them mobile and viable, because each sperm’s journey through the cervix and uterus is aided by millions of fellow travelers. Sperm count may have declined over the past century, but the count varies a great deal from place to place—higher in southern France than in Paris, in New York than in California, in Finland than in Sweden—for reasons that may be more connected to the specifics of the sample than to the health or age of the men (Merzenich et al., 2010).

Depending on the man’s age, each day about 100 million sperm reach maturity after a developmental process that lasts about 75 days. Anything that impairs body functioning over those 75 days (e.g., fever, radiation, prescribed and nonprescribed drugs, time in a sauna, stress, environmental toxins, alcohol, cigarettes) reduces sperm number, shape, and motility (activity), making conception less likely. Sedentary behavior, perhaps particularly watching television, also correlates with lower sperm count (Gaskins et al., 2013).

Age reduces sperm count, the probable explanation for an interesting statistic: Men take five times as many months to impregnate a woman when they are over 45 as when they are under 25 (Hassan & Killick, 2003). (This study controlled for frequency of sex and age of the woman.) Overall, low sperm count is common but often easy to remedy.

As with men, women’s fertility is affected by anything that impairs physical functioning—such as disease, smoking, extreme dieting, and obesity. As with men, age itself also slows down every step of female reproduction—ovulation, implantation, fetal growth, labor, and birth. Many infertile women do not even realize they have contracted one specific disease that causes infertility—pelvic inflammatory disease (PID). PID creates scar tissue that sometimes blocks a woman’s fallopian tubes, preventing sperm from reaching an ovum.

In the past 50 years, medical advances have solved about half of all fertility problems. Surgery repairs reproductive systems, and assisted reproductive technology (ART) overcomes obstacles such as a low sperm count and blocked fallopian tubes. Some ART procedures, including in vitro fertilization (IVF), which has led to an estimated 5 million births (Fisher & Guidice, 2013), were explained in Chapter 3.

Donor sperm, donor ova, and donor wombs can help individuals whose partner is infertile or who have no partner of the other sex: Birth through all of these means is biologically possible, and together they have led to tens of thousands of children as well as to dozens of moral questions.

Some uses of ART are morally acceptable to virtually everyone, especially when couples anticipate disease-related infertility. For example, many cancer patients freeze their sperm or ova before chemotherapy or radiation, allowing conception after they recover.

In another example, before 2000, doctors recommended sterilization and predicted early death for those with HIV; Now such individuals almost always use condoms for sex (to protect the uninfected partner) and live for decades. If the woman has the virus, drugs and a Cesarean can almost always protect the fetus; if the man is HIV-positive, sperm can be collected and washed in the laboratory to rid them of the virus, and, via IVF, pregnancy can occur (Sauer et al., 2009).

All ART procedures need expensive medical assistance, not usually covered by insurance. IVF also requires both biological parents to undergo special procedures. The woman takes hormones to increase the number of ova ready to be surgically removed, and the man must ejaculate into a receptacle. Then technicians combine the ova and sperm, typically choosing one active sperm to insert into each normal ovum. Ideally, zygotes form and duplicate. Then one or more healthy blastocysts are inserted into the uterus, which is ready for implantation via additional drugs.

Even with careful preparation, less than half of the inserted blastocysts implant and grow to become newborns. Some young women freeze their ova for IVF years later because the age of the ova is crucial (MacDougall et al., 2013). Miscarriages (perhaps one in three implanted embryos) increase with age.

In most European nations, public insurance covers the cost of ART, although some nations require proof of infertility, proof of marriage, and so on. In the United States, private insurance rarely covers ART, but federal military insurance does. That increases the rate of IVF among infertile African and European Americans, but not among Hispanics (McCarthy-Keith et al., 2010). More African and Latin Americans are infertile than European Americans, but their rate of ART is lower, for many economic and cultural reasons (Greil et al., 2011).

IVF to the Rescue In every nation some babies begin life in a laboratory dish, as IVF overcomes blocked Fallopian tubes, low sperm count, and other common fertility impediments. IVF now solves uncommon problems as well. In Kentucky, Avery Kennedy (left) began life via a donated frozen ovum, fertilized by Jared (shown here) and implanted in Wendy’s uterus. In Spain (right), a few hours after Roger’s conception, one stem cell was removed and tested for the gene for Huntington’s chorea. Since one of his parents (shown here) has that dominant gene, Roger had a 50/50 chance of inheriting it. Obviously, he did not.

AP PHOTO/BRIAN TIETZ
© JORGE Z. PASCUAL/EPA/CORBIS

When IVF children are not low birthweight, they develop as well as other children, not only in health, intelligence, and school achievement, but also in self-reported emotional development as teenagers (Wagenaar et al., 2013).

Parents may be more responsive to IVF children. This is suggested by a study in Jamaica, where IVF parents are more authoritative and less permissive or authoritarian than parents whose children were conceived spontaneously (Pottinger & – Palmer, 2013). There are at least two possible explanations: that the parents tend to be more mature, and that the children tend to be strongly wanted.

Menopause

During adulthood, the level of sex hormones circulating in the bloodstream declines—suddenly in women, gradually in men. As a result, sexual desire, frequency of intercourse, and odds of reproduction decrease. The specifics differ for women and men.

For women, sometime between ages 42 and 58 (the average age is 51), ovulation and menstruation stop because of a marked drop in production of several hormones. This is menopause. The age of natural menopause is affected primarily by genes (17 have been identified; see Morris et al., 2011; Stolk et al., 2012) but also by smoking (earlier menopause) and exercise (later).

In the United States, one in four women has a hysterectomy (surgical removal of the uterus), which often includes removal of her ovaries. If she was premenopausal, removal of the ovaries causes menopausal symptoms—vaginal dryness and body temperature disturbance, including hot flashes (feeling hot), hot flushes (looking hot), and cold sweats (feeling chilled). Natural menopause produces the same reactions, but not as suddenly and not in everyone. Early menopause, surgical or not, increases the risk of various health problems later on (Hunter, 2012).

The psychological consequences of menopause vary more than the physiological ones. Anthropologist Margaret Mead famously said, “There is no more creative force in the world than the menopausal woman with zest.” Some menopausal women have erratic moods, others are more energetic, still others become depressed (Judd et al., 2012).

Pausing, Not Stopping During the years of menopause, these two women experienced more than physiological changes: Jane Goodall (left) was widowed and Ellen Johnson-Sirleaf (right) was imprisoned. Both, however, are proof that postmenopausal women can be productive. After age 50, Goodall (shown visiting a German zoo at age 70) founded and led several organizations that educate children and protect animals, and Johnson-Sirleaf (shown speaking to the International Labor Organization at age 68) became the president of Liberia.

JENS SCHLUETER/AFP/GETTY IMAGES
©SALVATORE DI NOLFI/EPA/CORBIS

Over the past 30 years, millions of postmenopausal women used hormone replacement therapy (HRT). Some did so to alleviate symptoms of menopause; others, to prevent osteoporosis (fragile bones), heart disease, strokes, or dementia. Correlational studies found that these diseases occurred less often among women taking HRT.

Researchers now believe that, since women with more education and money were more likely to use HRT, the lower rate of disease was primarily the result of higher SES. In controlled longitudinal studies, the U.S. Women’s Health Initiative found that taking estrogen and progesterone increased the risk of heart disease, stroke, and breast cancer and did not prevent dementia (U.S. Preventive Services Task Force, 2002). A large observational study confirms the breast cancer risk: Women who took HRT were more likely to develop breast cancer (at the rate of 6 per 1,000 compared to 4 per 1,000) (Chlebowski et al., 2013).

HRT does reduce hot flashes and decrease the incidence of osteoporosis, but women who want those benefits need to weigh the costs. Surprisingly, culture seems more influential than cost-benefit analysis. For instance, Australian researchers confirm that estrogen reduces osteoporosis, so many Australian women take the hormone (Geelhoed et al., 2010). A study in Germany found that doctors hesitated to prescribe HRT, but at menopause most female gynecologists used HRT and male gynecologists gave it to their wives (Buhling et al., 2012).

Do men undergo anything like menopause? Some say yes, suggesting that the word andropause should be used to signify age-related lower testosterone, which reduces sexual desire, erections, and muscle mass (Samaras et al., 2012). Even with erection-inducing drugs such as Viagra and Levitra, sexual desire and speed of orgasm decline with age, as do many other physiological and cognitive functions.

But most experts think that the term andropause (or male menopause) is misleading because it implies a sudden drop in reproductive ability or hormones. That does not occur in men, some of whom produce viable sperm lifelong. Sexual inactivity and anxiety reduce testosterone—with a result superficially similar to menopause but with a psychological, not physiological, cause.

To combat the natural decline in testosterone, some middle-aged as well as older men have turned to hormone replacement (Samaras et al., 2012). Some women also take smaller amounts of testosterone to increase their sexual desire. But at least one longitudinal study with both sexes comparing testosterone supplements with a placebo found no benefits (sexual or otherwise) (Nair et al., 2006). Indeed, male HRT may cause heart disease and other problems (Handelsman, 2011).

About 2 percent of older men have very low testosterone levels and benefit from supplemental hormones. For most men, however, physicians are skeptical of benefits (Handelsman, 2011). One writes that men would be better off learning about “the health benefits of physical activity…. Tell them to take the $1,200 they’ll spend on testosterone per year and join a health club; buy a Stairmaster—they’ll have money left over for their new clothes” (Casey, 2008, p. 48).

All the evidence for both sexes finds that adult health depends more on health habits than on HRT. We discuss that next.