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February 22, 2003

Sex ratio at birth by country

Check out this page that clumps countries according to the ratio of male:female births.

Some notes:

Japan has a ratio of 1.05, China 1.15, which seems to be the East Asian spread. The Japanese prefer girls and unlike other East Asians seem to have successfully discouraged gender selective abortions.

The South Asian nations have sex ratios of 1.05/1.06, the same as the United States, despite the stereotype that sons are preferred. Why could this be? It might be that sex selective abortion is not accessible to most of the population because of monetary concerns. Additionally, South Asians may be more prone to carry more girls to term compared to East Asians , so sex selective abortions do not skew the ratio as much (I assume Japan at 1.05 is close to the natural rate of many East Asian populations, perhaps even shifted toward girls a bit because of couples that manage to find out gender in a country where 75% perfer girls) [1].

Finally, take a look at the countries with the most balanced sex ratios. Very interesting, do you see any pattern?

[1] There are many possibilites, more male fetuses might be spontaneously aborted, or, there might be more genetic males who did not develop the sex characteristics and so are recorded as female. Please note that abortion is illegal in Pakistan and Bangladesh, but legal in India. Nevertheless, the three countries have about the same sex ratio....

Posted by razib at 12:48 AM

Looks like yet another reason to consider moving to the Cayman Islands...

Posted by: jimbo at February 22, 2003 06:18 AM

What is the natural baseline? I don't think it's 1:1.

Posted by: zizka at February 22, 2003 08:51 AM

Jersey looks pretty stable and likely to remain that way for years.

Posted by: -R at February 22, 2003 10:19 AM

Baseline is 1.06:1.

More boys die at younger ages so it balances out by age 20 or so.

Of course, by 50, the ratio slips to favoring women.

Posted by: David at February 22, 2003 11:25 AM

in the united states it is 28...it is important for young men to know these things :) the real number of avail. women is lower than that because of older guys dating women in their 20s, and the lack of reverse balance.

Posted by: razib at February 22, 2003 12:43 PM

Razib, parts of India do have a tremendous gender imbalance among youth. Mostly the wealthier parts. At the census of India site you can see the sex ratios for Indians between the ages of 0 and 6.

In Punjab (very rich state), the 0-6 group has a ratio of 793 girls to 1000 boys.

In Bihar (very poor state) the 0-6 ratio is 938 girls to 1000 boys

In Kerala (less Gender bias) the 0-6 ratio is 963 girls to 1000 boys.

Full state data is here:

Compare rich north Indian states like Punjab and Haryana to poor North Indian states Bihar or Jharkand.

Posted by: Ikram Saeed at February 23, 2003 02:44 PM

Where do the data come from and which year they refer to? Thanks.

Posted by: Wei at May 4, 2003 02:47 AM