male-female birth ratio

[Xenocrates]

http://news.xinhuanet.com/english/2007-04/26/content_6032331.htm

In America, the proportion of boys dropped from 105.5 per 100 girls in 1970 to 104.6 in 2001; in Japan, the male-to-female ratio dropped from 106.3 boys for every 100 girls to just fewer than 105 per 100.

How significant is this and why is it happening? Is it a pollutant or a result of lifestyle change? Maybe medication is the cause? Or computer games . Or even the result of a sexual method change - personally I blame bush

 

[nc-1701]

Well this looks like good news to me

 

[Abaddon]

Well in theory it should be 1:1

 

[Urederra]

My guess (don't take it as a proven fact)

In theory it should be 1:1 ratio. In practice it is not because problems may arise during the pregnancy or delivery producing miscarriages/abortions. These miscarriages may have different survival ratios depending on the gender of the foetus. Since medicine advances, the miscarriages or abortions during delivery may be less frequent, bringing the practical ratio closer to the theoretical one.
Hope it makes sense. But don't take it as fact, I am just speculating.

 

[ArneHD]

Well in theory it should be 1:1

Actually, in theory there should be a slight bias in favour of men, as the Y chromosone is very light in comparison to the X chromosone. Therefore male sperm are slightly quicker and more likely to reach the egg than female sperm.

 

[Abaddon]

then perhaps the Y chromosone is getting fatter as the generations continue?

 

[Yoda Power]

Well in theory it should be 1:1

Remember that men also die younger than women, thus there have to be more men in order to be balance.

 

[Urederra]

Actually, in theory there should be a slight bias in favour of men, as the Y chromosone is very light in comparison to the X chromosone. Therefore male sperm are slightly quicker and more likely to reach the egg than female sperm.

OK, that makes more sense, and now I recall reading something about theoretical ratio not being 1:1.

 

[Abaddon]

Remember that men also die younger than women, thus there have to be more men in order to be balance.

Arf? How would that affect birth rates? People tend to die AFTER breeding age, so any genes controlling ageing are not under selection pressures

 

[Yoda Power]

Arf? How would that affect birth rates? People tend to die AFTER breeding age, so any genes controlling ageing are not under selection pressures

I knew that question would be asked.

I don't have a clear answer on why, but it seems mother nature have a way of making things work.

 

[Godwynn]

Let's look at China's male female ratio!

 

[Xanikk999]

This is not really significant. Just because a trend shows a decreasing birth rate does not mean we will eventually have a negative birth rate. I see it as a minor trend that will be reversed and then go back and forth again.

 

[Mise]

I always thought that there were more boys than girls because boys were likely to die before girls (biologically speaking now, ignoring environmental/social factors) and so there would be too few boys at "mating age" to continue the population.

 

[Kozmos]

Evolution. Why have two sexes when one is easier to maintain. Asexual reproduction ftl.

 

[Swedishguy]

Who in their right mind would want to be a male?

 

[ArneHD]

Who in their right mind would want to be a male?

People who want to become Prime Ministers, Presidents Etc.?

 

[Mirc]

I think the best way to control population overcrowding is finding a way to select the gender of the children before they are born - use a 1:50 male/female ratio and everyone is happy.

 

[PrincepsAmerica]

Who in their right mind would want to be a male?

lol gender confusion

 

[mrt144]

if you had a male mentality and a female gender, the world could be yours. in theory.

 

[Kozmos]

if you had a male mentality and a female gender, the world could be yours. in theory.

Arent those lesbians and feminists?