Posted on 08/08/2007 2:47:23 PM PDT by blam
Rich mothers 'have more sons'
By Roger Highfield, Science Editor
Last Updated: 12:01am BST 08/08/2007
Rich, married and well-educated women tend to have more sons while those who are unhealthy and poorer tend to have more daughters, according to a study.
Well-off women produce more sons
Researchers studied 50 million people and found that mothers in 'good condition’ - those who were married, better educated and younger - bore more sons than mothers in 'poor condition’.
The reason, simply put, is that women are tougher than men so according to evolutionary theory women living in poorer communities are predisposed to have daughters to ensure survival of the family line because the men are more at risk of dying younger.
The research, carried out in America and published today in the Proceedings of the Royal Society also holds up a mirror to the poor health and education of black people in America, where black mothers have long born fewer boys than white mothers, who have seven more for every thousands births.
And it has a depressing implication for countries such as India and China where female infanticide occurs, since the findings suggest that these countries cannot avoid having an excess of daughters.
The ideas has proved true for a range of species, such as insects, birds, pigs, sheep, dogs, mink and deer. The study by Prof Lena Edlund and Prof Douglas Almond of Columbia Univetsity, New York, used the “largest and most detailed data set yet employed.”
She said: “We find that married, better educated and younger (advantageous from a biological perspective) mothers are more likely to bear sons.
“For instance, relative to a mother with some college education, a mother without a high school degree was approximately 0.6% less likely to bear a boy.
“Infant deaths were more male if the mother was unmarried and young.” Being married seemed to help the survival of boy babies, though this had only one third the effect of being white as opposed to black in America.
“In the case of marital status, the results are unambiguous,” they conclude. “Married mothers bore more sons and infant mortality reinforced the pattern observed at birth. That is, married mothers were not only more likely to bear sons, but marriage was also associated with reduced risk for male infants.”
The work provides powerful confirmation of an idea set out more than three decades ago by Robert Trivers, an evolutionary biologist, and Dan Willard, a mathematician, who boil life down to one factor - having as many offspring as possible and thus passing on as many genes to future generations as possible.
The “Trivers-Willard hypothesis” argues that strong healthy women tend to have sons in order to ensure her genes and family line are passed on. These sons are in turn strong and outdo other weaker male offspring to reproduce, thus ensuring survival of the fittest and of the family line.
However, weaker or poor mothers tend to have weaker sons who do not do well and are more likely to die early - earlier than women in the same society.
To ensure survival of the family line, the women tend to have daughters because they are more likely to be survive long enough to become parents themselves.
Although the results strictly apply to the United States, Prof Edlund speculated that in developing countries she would expect the effect of a bias towards girls at the bottom social strata to be more pronounced because infant mortality is up to ten times greater than seen in America.
There is much emphasis in these societies on the need for a son to carry on the family name, said Prof Edlund. “For the son to do this, he will need a partner, and in a society where everybody hankers for sons, it is the poor whose sons would not find spouses. Thus, they might be better off with a daughter - there would be no continuation of the family name, but at least of its genes.”
Bunk...absolute tripe...
Bovine scatology : )
Or could it be that monogamous societies have an even number of each sex, and polygamous societies have more females?
I always knew I was middle class. Two girls and three boys.
Not in my case but I did read something about this, years ago though. There were statistics on babies in distress and premies. The girls tended to be a little bit better survivor.
There have also been correlations that a vegetarian diet increases the odds of having a girl. That effect even held true for upper class white vegetarians in England. Perhaps the link is lack of meat to lack of boys. The poor are more likely to be vegetarian because they can’t afford animal protien.
yeah but girls are easier to deal with until puberty...
Only boys for me and mine. I didn’t know she was rich. Hmmm
I’m with you. Diet seems to be the most likely variable which would account for this, assuming of course that their recitation of the data is accurate.
Exactly what I have. Two wonderful daughters and three great boys!
“The reason, simply put, is that women are tougher than men...”
Guess we should have sent shiploads of women to Iwo Jima and Normandy. The war would have ended immediately if not sooner.
what a bunch of bologna!
does not hold true for any family in our immediate family.
Lies, damn lies, and disembodied statistics.
This garbage was published?
LOLOLOLOLOLOLOL
I guess you’re rich and healthy, Leda, and I’m poor and unhealthy.........
ROFLMSS!!!!!!!!
Where do the poor and healthy folks fall in here????
Maybe so, my mother was poor always and had 9 girls and 3 boys, one boy died at 4 years of age, all the girls still live, with the eldest being 58. The 9 girls produced 12 children, the 2 surviving boys produced 5.
What a waste of money and time.
its called “abortion”...and richy women can get them really easily and sneaky as well...
and my mom and dad were poor relatively, and they produced 4 boys and 2 girls.....so there you go...
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