and here i thought it was so children would have mothers young enough to protect and nurture before they are to old to properly do so... sixty year old mothers play hell chasing around terrible twos
Posted on 06/13/2013 5:44:55 PM PDT by rickmichaels
TORONTO – Theories abound as to why women go into menopause, but the latest hypothesis being put forward suggests it may be men — or specifically their preference for younger mates —that has led to women’s loss of fertility at a certain age.
Researchers at McMaster University believe that over tens of thousands of years, a lack of reproduction among older women has given rise to menopause as an unintended result of evolutionary natural selection.
Using computer modelling, the researchers found that over time, competition among men of all ages for younger mates left older females with much less chance of reproducing.
“We are saying somewhere along the line, men began to change their preference in mating,” said evolutionary biologist Rama Singh, co-author of the study published in this week’s issue of the journal PLOS Computational Biology.
“What we’re saying is that menopause will occur if there is a preferential mating with younger women and older women are not reproducing,” he said Thursday from Hamilton.
Singh said women would have had children when they were younger — from 15 to 30, based on the computer model.
Any genetic mutations that caused an end to fertility later in life would be passed down from generation to generation, he said.
And over time, an accumulation of such mutations harmful to female fertility ended up producing a menopausal period that became part of the overall human female genome, the hypothesis suggests.
“It’s a very simple theory. What it does is it demystifies menopause. … It becomes a simple age-related disease, if you can call it that,” said Singh.
“That’s just like all the mutations that affect our aging — white hair, weak muscles, this and that. These are mutations which affect fertility.”
The researchers’ hypothesis runs counter to prevailing theories about menopause, including the widely held “grandmother theory.”
That theory suggests that women evolved to become infertile after a certain age to allow them to assist with rearing grandchildren, thus helping to promote survival of their children’s offspring.
Kristen Hawkes, an anthropologist at the University of Utah in Salt Lake City, is among the leading proponents of the grandmother theory.
Other primates, such as chimpanzees, do not live as long as humans, but females of the species have a loss of fertility, or parturition, at similar ages to their human counterparts, she said. Female chimps rarely live beyond their child-bearing years, usually dying in their 30s or sometimes their 40s.
“The preference men have for young partners is a striking contrast with other primates,” Hawkes said by email, noting that it’s been well-documented that male chimpanzees prefer older females as mates.
“My guess about that has been it’s a consequence of our life history — something selection would favour after — not before — our grandmothering life history evolved … when women continue to be healthy and competent beyond their fertility.”
Singh, however, doesn’t believe the grandmother theory holds 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 said.
“This theory 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.”
Besides ending reproduction, menopause also affects a woman’s health as hormonal changes increase the risk for such conditions as cardiovascular disease and osteoporosis, said Singh.
He hopes the new theory might spawn research into ways to prevent menopause, which would lengthen a woman’s reproductive life while also helping to maintain better health as she ages.
“Until now, it has been something that you could not do anything about except (deal with) the symptoms.”
What cockeyed lesbian came up with blaming menopause on men? Of course it’s mens’ fault, everything negative in a poor helpless woman’s life is a man’s fault somehow. Good grief this is tiresome. Maybe women could just deal with the hand life dealt them and not seek others to blame? When will this form of equality kick in? Because I’d sure welcome it with open arms, I’ve heard this ridiculous externalization of fault all my life.
It seems to me that cause and effect are reversed in this hypothesis - if older women didn’t become infertile (or otherwise incapable of raising a child), there wouldn’t be evolutionary pressure for men to strongly prefer young women.
I go with a modified version of the grandmother hypothesis - if having a baby at 50 kills you, that baby will probably die, and the baby you had at 46 and the one you had at 42 won’t do so well either.
“That’s because men’ll pause before they ever go near them again, son...”
Bush’s Fault!
(Ducks....)
It is because the body can no longer stand the strain of pregnancy.
There used to be a saying, "a tooth for every child", they were not kidding. Pregnancy is hard on the body. Especially in the days before prenatal care.
of course, it’s mens’ fault. leave it to women to blame menopause on men.
no wonder more men die early.
and here i thought it was so children would have mothers young enough to protect and nurture before they are to old to properly do so... sixty year old mothers play hell chasing around terrible twos
people’male’too uch money to stop blaming others.
look at the blacks and minorities blaming everyone for all their problems. slavery ended in 1865, haven’t had any slaves since then, all former slaves are long dead, all former slave’owners are long dead,’most whites here now emigrated after slavery ended, no blacks alive today were slaves, yet it’s like it only ended when barry was elected. rush was talking about an interview he had with a black activist a long time ago before his show, and how when the activist when asked, how long would reverse discrimination go on, he said it would never end.
this is why you can’t placate any liberal. they are fighting and love the fighting, they don’t want the struggle to end, it never ends, nothing is ever enough, they just want to use the dialectic to get more and more extreme.
never enough.
these people must be fought at every level and these are the people we’ve fought world wars against, and cold wars, against.
This article has to be one of the stupidest things I’ve ever heard coming out of *scientific research*.
LOL, I was wondering how long it would take for that accurate description to be posted.
It’s as backwards as the researchers who blamed wearing bras on sagging breasts, not stopping to think that women with sagging breasts tend to wear bras.
If this is what passes for scientific research these days, the scientific community is in way more trouble than it realizes.
It’s because there are only so many eggs a woman is born with and they run the hell out.
Simple.
It just takes a REAL man to not need the younger woman and appreciate the one who knows exactly how he likes his eggs, his shirt collars and/or her paycheck. LOL
Prior to the development of good stockades the normal human lifespan rarely exceeded 30 to 35 years. With the arrival of village life, and good stockades, the older folks no longer needed to be able to run as fast to find safety from attack.
——This article has to be one of the stupidest things I’ve ever heard coming out of *scientific research*.-——
I read it twice thinking maybe I was missing some point....to understand his theory...
The only good thing is Canadian taxpayers paid for this gibberish...and not us...
It’s political science, like “climate change.”
Bush’s fault.
Oh, that’s just silly.
The researcher promoting this theory is a man.
Huh!? Menopause is what it is,the woman has run out of eggs through her life cycle and that is that. Young women are supposed to be running after their little ones, not 50 year olds. Who wants a newborn at 50 or 60? Nature, thank goodness, gives us a break before we die. LOL
What an ignorant theory.
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