Like a Virgin (24 page)

Walking marriages may appear to sanction promiscuity among young Mosuo women, but these arrangements are more like a form of serial monogamy, which is widely and happily practised across the
Western world. The main difference here is that in a Mosuo village there is no stigma attached to single motherhood. This is the norm, and mothers continue to live with their extended families
– grandmother, mother, cousins, aunts, and uncles – as they raise their own children. Uncles stand in for the father when it comes to providing a male role model. And this means that
any woman can have a child
when
she chooses, without the stigma of single motherhood – something that many Western women cannot say of themselves.

There have always been cultural norms around reproduction – norms involving what religion, caste, or race a partner should belong to; whether polygamy or monogamy is
acceptable; which children are top of the pecking order to inherit property; whether or not an elderly man is an acceptable mate for a younger woman. But a recent survey carried out in more than
seventy countries shows that our values about reproduction are tied not just to our family’s status and access to property, but also to the larger context of economic development. In
industrialized societies, this encompasses a remaking of the idea of family that is completely changing the way we have babies – and what the future will look like.

At the most basic level is a change in our interactions with close family members, who are now often replaced with friends, colleagues, and peers in our social lives. This is especially true
early in adulthood, when people enter the workforce and establish their own homes. At the same time, the level of education you’re expected to have in order to get a job has increased, which
means that people are staying at school, at university, and in training, and building up debt, into the early years of adulthood. Men and women contemplating a family of their own face a long list
of obstacles: to be able to afford appropriate housing; to afford or clear university debts; to achieve job stability and a level of wages that can support more than one person (or two); and to
make a career and childcare compatible. And that’s setting aside the very modern desire to win the lottery of finding a ‘good’ partner, in romantic terms. With all of these
obstacles standing in the way, having children is less of a priority – or, at least, less of an immediate one. So men and women in the industrialized world are increasingly
waiting to start families until their mid-thirties, or even into their forties.

Global fertility is in general decline. This trend is most pronounced in industrialized countries, especially in Western Europe, where the population is projected to decline dramatically over
the next fifty years. According to the US Census Bureau, nearly all the world’s developed regions are reporting fewer births, and about half the world’s population lives in regions
where the number of births is fewer than necessary to achieve long-term population stability. And that’s just in the short term. Of the 223 countries listed in the CIA’s
World Fact
Book
, ninety-four now post a fertility rate of less than two children per woman – a rate that means fewer kids to support ageing parents. The ninety-four countries on the CIA list include
China, Japan, and South Korea, all of which have lower birth rates than do the countries of Europe. Birth rates are certainly falling in Europe and in the US due to the current trend towards
starting a family later in life. The US rate squeaks above two, at 2.05 – putting it just outside this club. The European Union’s statistics agency predicts that by 2050 the
federation’s population will drop by around seven million.

Studies show that seventy-four percent of women who definitely or probably want children in practice delay getting pregnant because of relationship issues. For most women, it’s not work or
training worries, or other distractions, that cause the delay, but basically because they hadn’t yet found the ‘right’ partner. That’s not to say that career ambitions
don’t play a role. The second most common cause for delayed motherhood in developed countries is the social rewards that come to those who achieve professional success. Things like
educational status, a prestigious or lucrative career, and the allure of luxury (and sometimes not-so-luxury) goods interfere with a woman’s opportunities to reproduce, because acquiring the
trappings of
success takes energy and time, right at the peak ages for fertility.

These sociological and economic shifts have had the effect that, in industrialized countries, the average age of first childbirth is increasing, and more women are having no children at all.
That’s one part of the story. The other part of it comes down to the limits of the human body. Because, of course, the bane of any woman who delays having children will be her age. Seven out
of ten women surveyed who said they wanted children are concerned or very concerned about whether they will actually be able to have a baby by the time they get around to trying.

For many animals, fertility fades alongside all the other functions of the body – a slow, steady decline that comes with age. A man becomes increasingly infertile with
age, but may still be able to eke out a sperm and fertilize an egg into his seventies or eighties – around the time when the rest of his body is starting to shut down. A woman, as we have
seen, loses the ability to reproduce some thirty years before then, and the process comes as something of a shock. Usually, all of a woman’s other organs still function, her faculties are
undiminished, her health remains robust – all the biological stuff remains more or less the same, except she can no longer have a baby.

Becoming sterile with age is not exclusive to humans, technically. Rodents, whales, dogs, rabbits, elephants, and domestic livestock experience an abrupt end to fertility too. Other primates,
such as chimpanzees, gorillas, baboons, and macaques, also have a ‘biological clock’ and experience drops in fertility as they age. Still, female chimpanzees in the wild have been known
to give birth at very advanced ages – even into their fifties and sixties – surpassing the UK natural-birth record set
by Kathleen Campbell at the age of
fifty-five. (Interestingly, the male chimps seem to prefer mating with these older females – a point that doesn’t often get trotted out in evolutionary psychology. Perhaps, thinking
like a Darwinist, it’s because the older female chimps have displayed their fertility – most, it is presumed, have previously given birth.)

What is unique to humans among the primates is that our females have the potential to survive for a very long time after they become sterile. Though today humans enjoy longer and generally
healthier lives – with access to better medical care than our ancestors had just three generations ago – the timing of the menopause has remained more or less the same since the days of
the hunter-gatherers. Women stop being fertile around the age of fifty, and women live on average to be seventy years old – and much older in some countries. (In Japan, the average life
expectancy for a woman born today is eighty-six years, and both the UK and the US come in at over eighty.) In reproductive terms, this is a waste of about one third of one’s life. It’s
even worse when you consider the maximum life span for humans of about 122 years. If a woman lived that long, she would spend nearly sixty-nine percent of her life without the capacity to have
babies. This isn’t fantastical speculation; by 2025 the global population of women aged sixty-five or older is projected to be eight hundred and twenty-five million.

In theory, this long stretch of sterility in life may be an evolutionary adaptation, because women stand to gain greater genetic benefits in the long term by helping their children to reproduce
successfully rather than by continuing to have more babies of their own, an idea called the grandmother hypothesis, first put forward by University of Utah anthropologist Kristen Hawkes. When an
older woman becomes infertile, it helps to ensure her longevity – giving birth to babies with big heads via a narrow birth canal is a difficult endeavour at any age, but in
older age the risk of death or medical complications is much higher. But the menopause also has a social side benefit: it frees up older women to care for their daughters’
babies rather than compete with younger, more fertile women for sperm. (Of course, this assumes that the menopause marks a change in sexual activity, not just in reproductive capability. And the
changes in hormones at this time do, indeed, make a difference.)

Compared to other animals, human babies are markedly dependent on adults (usually, mothers) for an extended period of time, which means that if a mother were to die, having a grandmother around
may be key to a child’s survival. Studies of pre-modern hunter-gatherer groups with no access to modern medicine have found that women with a prolonged, post-reproductive lifespan have more
grandchildren, and that these children are significantly more likely to survive to adulthood if they have a grandmother’s assistance. No other relatives have a similar effect.

For most mammals, a mother is more important than a father in determining an infant’s survival into adulthood.
Homo sapiens
are considered to be unique, however, in the extent to
which the family has traditionally provided help and care for our young. So opportunities for inter-generational co-operation may have been one of the evolutionary architects of women’s early
and prolonged period of sterility. A woman’s reproductive success depended on having a sterile mother by the time she was caring for a brood of her own. The knock-on effects of menopause
would have been very positive for a post-reproductive woman (provided, of course, she happened to have had a daughter in the first place). This may be why the menopause happens bang in the midlife
of a woman, but nothing similar happens in a man.

The experience of going through the menopause is not simply a question of turning off the hormones that allow egg release
and pregnancy; it is essentially a case of organ
failure, with the ovaries shutting down completely, and some doctors consider the process to be as much of a medical threat as the failure of another organ, say, the gall bladder or kidney. The
hormonal changes affect a woman’s entire physical and emotional well-being. Post-menopausal women are at increased risk for several major diseases, including cardiovascular disease, breast
cancer, and osteoporosis. The female biological clock counts down not just to the end of fertility but to the beginning of a new body, with different needs.

Still, although the onset of menopause seems to be an immutable part of nature, it appears to be amenable to manipulation. The incessant ticking can be speeded up or slowed down. We know, for
example, that exposure to certain chemicals or radiation from cancer therapies can trigger premature menopause in young women. The menopause also happens earlier in women who smoke cigarettes.

Why, in evolutionary terms, the end of fertility in otherwise healthy women is so clearly marked has long been a great puzzle. A simple solution would be to work within the limits of what human
biology allows. Fertility is subject to hormonal regulation, just like it is in every other mammal, so why not just whip up some hormones in the lab and trick the body into reproduction well beyond
its ‘sell-by’ date? The production of hormones can be easily influenced by environmental conditions too.

For humans, though, reproduction is also socially regulated, from the acceptability of walking marriages among the Mosuo to the top-down condemnation of having ‘unprotected sex’ with
someone who isn’t a long-term partner. And social regulations don’t live in some world separate from our biology. Take, for instance, the way in which sexually transmitted diseases
affect fertility. STDs, such as chlamydia, cause infertility – and
these diseases are on the rise. Chlamydia has long been known to cause damage to the Fallopian tubes,
making women less fertile; recently, it has been discovered that the bacteria hurt sperm too – men aren’t simply carriers of the disease. When men are infected, the bacteria physically
‘sit’ on sperm, gripping on to the sperm’s tail at intervals, which reduces a sperm’s ability to swim to an egg. The bacteria can also trigger sperm death. The jury is still
out on whether treating chlamydia with antibiotics makes any difference to sperm health, as men who have had chlamydia can remain infertile long after the bacteria have been cleared from the
reproductive system.