“The appealing thing about younger women is
their outlook on life. They tend to be untainted by experiences that have
hardened older women. For example, when a woman’s been lied to a lot after
years of dating, she always thinks that you’re lying to her, too. And that’s a
turn-off. Younger women are less cynical, and that’s a big draw.”
— Alan, 52, New York, NY
— Alan, 52, New York, NY
“When a guy reaches a certain age, he
worries he will see his youth and vitality wane. A younger woman reaffirms for
me that I’ve still got it going on.”
— Mike, 48, Orlando, FL
— Mike, 48, Orlando, FL
“One advantage of dating a younger woman is
that you can play ‘cruise director’ — i.e., show her all your secret favorite
places that she probably hasn’t experienced yet. They’re easier to impress and
very willing to be escorted around. Women like it when you have a plan and it’s
well-executed.”
— Bill, 39, New York, NY
— Bill, 39, New York, NY
From Match.Com
After decades of laboring under other theories that never
seemed to add up, a team led by biologist Rama Singh has concluded that what
causes menopause in women is men.
Singh, an evolutionary geneticist, backed by computer models
developed by colleagues Jonathan Stone and Richard Morton, has determined that
menopause is actually an unintended outcome of natural selection -- the result
of its effects having become relaxed in older women.
For thousands of years (at least), men have, on average,
mated with younger women, Singh said. That's because, if all else is equal,
"those who reproduce earlier, their genes are passed on faster”. Early on,
both men and women in the model reproduced until death. But over time, the model
found, men's preference for youth reduced older women's odds of reproducing.
Simultaneously, people accumulated random mutations, some of
which decreased later-life reproductive ability. But since older women were
left out in the cold anyways, those mutations didn't impact their reproductive
success, whereas mutations in men that could reduce late-life reproduction were
weeded out. (Men who stopped reproducing at some point in life would produce
fewer offspring than those who didn't, and the late reproducers would
outcompete those who stopped breeding earlier.)
Over 50,000 to 100,000 years, the accumulation of all those
mutations could have led to universal menopause, the researchers suggest.
Menopause would then be another form of aging akin to graying hair or wrinkles.
If later childbearing becomes the norm, as current societal
trends suggest, women who can reproduce at older ages might gain an
evolutionary advantage, and menopause could, in theory be pushed later, Singh
said. But it's more plausible that technological changes such as fertility
treatments will artificially extend women's ability to reproduce, Singh said.
So, while conventional thinking has held that menopause
prevents older women from continuing to reproduce, in fact, the researchers'
new theory says it is the lack of reproduction that has given rise to
menopause.
Menopause is believed to be unique to humans, but no one had
yet been able to offer a satisfactory explanation for why it occurs, Singh
says. The prevailing "grandmother
theory" holds that women have evolved to become infertile after a
certain age to allow them to assist with rearing grandchildren, thus improving
the survival of kin. Singh says that does not add up from an evolutionary
perspective. "How do you evolve infertility? It is contrary to the whole
notion of natural selection. Natural selection selects for fertility, for
reproduction -- not for stopping it," he says.
The new theory holds that, over time, competition among men
of all ages for younger mates has left older females with much less chance of
reproducing. The forces of natural selection, Singh says, are concerned only
with the survival of the species through individual fitness, so they protect fertility
in women while they are most likely to reproduce. After that period, natural
selection ceases to quell the genetic mutations that ultimately bring on
menopause, leaving women not only infertile, but also vulnerable to a host of
health problems.
"This theory says that natural selection doesn't have
to do anything," Singh says. "If women were reproducing all along,
and there were no preference against older women, women would be reproducing
like men are for their whole lives." The development of menopause, then,
was not a change that improved the survival of the species, but one that merely
recognized that fertility did not serve any ongoing purpose beyond a certain
age.
For the vast majority of other animals, fertility continues
until death, Singh explains, but women continue to live past their fertility
because men remain fertile throughout their lives, and longevity is not
inherited by gender. Singh points out that if women had historically been the
ones to select younger mates, the situation would have been reversed, with men
losing fertility.
University of Utah anthropologist Kristen Hawkes, grandmother
hypothesis supporter, whose work deals with the evolutionary origins of
menopause, points out that great apes, with whom we share a great deal of
evolutionary history, exhibit a similar pattern of losing fertility in their
mid-40s. The difference is that while the apes' fertility rates seem to be in
sync with those of humans, their longevity rates aren't. "They usually die
before they get to those post-fertile years," she says. "They get to
be old ladies, gray and frail, while they're still cycling."
But Hawkes acknowledges the human male's apparent difference
in taste. "I agree the preference men have for young partners is a
striking contrast with other primates — especially since it is well-documented
that chimpanzee males prefer older females," she says.
There are other experts, who are skeptical of this theory as
well. “I know we like to blame men for a lot of things, but I don’t think this
can be one of them,” Dr. Rebecca Brightman, a clinical instructor of
Obstetrics, Gynecology and Reproductive Science at the Icahn School of Medicine
at Mount Sinai Hospital, who wasn’t involved in the study. Brightman said there
are some Darwinian aspects of menopause, especially the high risks involved for
both mother and child when older women become pregnant. “Pregnancy takes a toll
on a woman’s body,” she said. “There’s an evolutionary advantage to being
incapable of having children later in life. Mothers want to be around to care
for their children.”
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