I have read that the number of males born annually relative to that of the
number of females, in the human population, is approximately a constant of
51/49. Since males are at a greater risk of death this difference might
help
promote a more equal distribution at the time of fertility.



My first question is this: how is this proportion maintained? I am at a
loss
to understand how it could be maintained except through feedback. If this
is
so, by what means does this feedback assert itself? Is it, for instance,
conceivable that we unconsciously modulate the likelihood of male versus
female birth via observations made in our brains?



My second question is this: In lions we see social groups (i.e. prides) in
which females outnumber males by several-to-one. Our species has a more
one-to-one ratio. First, is there a difference in the birth ratios of
females to males between lions and humans? Certainly, a male lion fights
more for the simple opportunity to reproduce than we do. Is there in fact
a
difference between the nature of male competition between lions and
humans?
Is it that lions compete more for the simple opportunity to reproduce
whereas humans compete more for the most highly prized females?



John Leonard

I have read that the number of males born annually relative to that of the
number of females, in the human population, is approximately a constant of
51/49. Since males are at a greater risk of death this difference might help
promote a more equal distribution at the time of fertility.



My first question is this: how is this proportion maintained? I am at a loss
to understand how it could be maintained except through feedback. If this is
so, by what means does this feedback assert itself? Is it, for instance,
conceivable that we unconsciously modulate the likelihood of male versus
female birth via observations made in our brains?

I have read that the number of males born annually relative to that of the
number of females, in the human population, is approximately a constant of
51/49. Since males are at a greater risk of death this difference might help
promote a more equal distribution at the time of fertility.

My first question is this: how is this proportion maintained? I am at a loss
to understand how it could be maintained except through feedback. If this is
so, by what means does this feedback assert itself? Is it, for instance,
conceivable that we unconsciously modulate the likelihood of male versus
female birth via observations made in our brains?

My second question is this: In lions we see social groups (i.e. prides) in
which females outnumber males by several-to-one. Our species has a more
one-to-one ratio. First, is there a difference in the birth ratios of
females to males between lions and humans? Certainly, a male lion fights
more for the simple opportunity to reproduce than we do. Is there in fact a
difference between the nature of male competition between lions and humans?
Is it that lions compete more for the simple opportunity to reproduce
whereas humans compete more for the most highly prized females?

I have a feeling that the answer is most likely as simple as pure chance. It's
like flipping a coin. If you flip the coin enough times 50% of the time, it'll
land on Heads. Now imagine flipping that coin billions of times. Male/Female;
you have a 50/50 chance of getting either. That is of course excluding the rare
chances the coin doesn't land on it's edge.

I have a feeling that the answer is most likely as simple as pure chance. It's
like flipping a coin. If you flip the coin enough times 50% of the time, it'll
land on Heads. Now imagine flipping that coin billions of times. Male/Female;
you have a 50/50 chance of getting either. That is of course excluding the rare
chances the coin doesn't land on it's edge.

The laws of probability show that when flipping coin, you will not get
a 50/50 ratio of heads to tales. One side is always a little more
likely.

The laws of probability show that when flipping coin, you will not get
a 50/50 ratio of heads to tales. One side is always a little more
likely.

About 40/60 in favor of tails.

Why do the numbers "favor" more male births?

Why do the numbers "favor" more male births?

They don't. The numbers "favor" female births as the world's population is
estimated to be 51% Female.

I have read that the number of males born annually relative to that of the
number of females, in the human population, is approximately a constant of
51/49.

Hi Eliza,

I wrote:


Why do the numbers "favor" more male births?


You replied:


They don't. The numbers "favor" female births as the world's population is
estimated to be 51% Female.


An excellent point... But, the original question was about births, not
about survival. Mr. Leonard wrote:


I have read that the number of males born annually relative to that of the
number of females, in the human population, is approximately a constant of
51/49.


I wish I could answer his question with authority, but I am not
trained in anthropology. Please take my attempt at an explanation for
what it is worth.

If I may be obnoxious enough to add something: Birth rates and
mortality rates within a species can be different. In humans, for
example, women tend to live longer than men. So, even if more males
are born, it is possible for a greater number of females to be alive
at any given moment. This would account for 51% of the _living_ human
population being female.

Respectfully,
Chesapean

I would also like to add, that males tend to engage in more dangerous
activities (a higher degree of thrill seeking and more thrill
seeking activities). This also leads to higher male mortality at an
earlier age - car crashes, combat and rock climbing are all examples
of activities that kill more males than females. From an anthropoligical
perspective these activities would be hunting and territory
defense/acquisition.

The inital birth rate favors males slightly in part to compensate for this.

Steve