Razib Khan One-stop-shopping for all of my content

October 25, 2012

Putting a stop on the biological clock

Filed under: Fertility,Health — Razib Khan @ 1:41 am

Egg freezing enters clinical mainstream:

Egg freezing is no longer an experimental procedure, according to the American Society for Reproductive Medicine (ASRM), which on 22 October issued new guidelines on the controversial practice. The change in policy is expected to accelerate the growth of clinics that offer egg freezing to women who face fertility-damaging treatment for cancer or other conditions, and to women wishing to delay having a baby — although the society stopped short of endorsing the procedure for that purpose

You can read the full guidelines, with caveats, online. Last I checked this costs on the order of $10,000. Nothing to sneeze at, but definitely not insane when you consider how much money many couples spend on fertility technologies when women are between 35 and 40.

And of course I recommend freezing sperm too. That’s far less costly.

August 15, 2012

Who shall inherit the earth?

Filed under: Data Analysis,Demographics,Fertility — Razib Khan @ 9:44 pm

There was a question below in regards to the high fertility of some extreme (“ultra”) religious groups, in particular Haredi Jews. The commenter correctly points out that these Jews utilize the Western welfare system to support large families. This is not limited to just Haredi Jews. The reason Somalis and Arabs have fertility ~3.5 in Helsinki, as opposed to ~1.5 as is the norm, is in part to due to the combination of pro-natalist subcultural norms, and a generous benefits state. Of course we mustn’t overemphasize economics. Israel’s decline in Arab Muslim fertility but rise in Jewish fertility in the 2000s has been hypothesized to be due to different responses to reductions in child subsidies by Muslims and the Haredi Jews. In short, the former reacted much more strongly to economic disincentives in relation to the latter.

A bigger question is whether exponential growth driven by ideology can continue indefinitely. I doubt it. Demographics is inevitable, but subject to a lot of qualifications. Haredi political power in Israel grants some benefits, but at the end of the day basic economics will serve as a check on the growth of the population of this sector. Similarly, barring ...

July 10, 2012

Toward healthier gestations

Filed under: Culture,Eugenics,Family,Fertility,Personal genomics,Reproductive health — Razib Khan @ 6:44 pm

Neuroskeptic has a post up, The Coming Age of Fetal Genomics:

So they don’t. Instead, they buy a $100 test kit, they each provide a small blood sample and send it off to one of the companies offering fetal genome testing. At the testing lab, they can separate out the mother’s DNA from that of the fetus, both of which are present in the mother’s blood. By comparing the fetal genome to the mother’s and father’s, it’s easy to spot de novo mutations. If a certain gene doesn’t match either the mother or the father’s sequence, it’s mutated.

A few days later the results are back. There are several mismatches detected. Most are benign – they’re not predicted to have any biological effects. But there’s one, a deletion of a few thousand bases in a gene involved in brain development. This deletion is predicted to raise the risk of epilepsy and autism from 1% to 10% apiece. The parents now have a decision to make. The mutation is a one off, it’s not inherited. If they conceive again… roll the dice again… and it’ll be gone. Do they terminate?

Like the adverts say, “Some people disagree with this, but we say there’s only one ...

December 30, 2011

Eggs: quantity and quality

Filed under: Fertility,Medicine — Razib Khan @ 3:05 am

In my post below on selection for the “better” zygote Michelle observes that “This would be relatively easy for the father, not so much for the mother.” I took her to mean either of two things,

1) Extraction of eggs is a major surgical affair. Extraction of sperm is not.

2) Males generally have many more sperm to contribute than females.

The latter issue made me go look for data on human females, by age. The paper A systematic review of tests predicting ovarian reserve and IVF outcome had what I was looking for. First, let’s review the cumulative distribution of fertility curves for women:


The way I read the figure 50% of women are sterile at 41. 50% begin their fertility drop at 31. Note that a small, but significant, minority of women are already sterile by age 35. People talk about fertility curves, but less weight is given to the fact that the curve varies in terms of its chronology!

Second, let’s look at the number and quality of ovarian follicles over time (they correspond to number of incipient eggs):

This figure is not easy to read. But you can see that at age 20 there are ~100,000 follicles. That number seems to drop by a little less than half by 30, and is at 20,000 by 40. But by this point 25 percent are of “poor quality.”

November 1, 2011

The Arab world’s demographic transition

Filed under: Data Analysis,Fertility — Razib Khan @ 9:24 pm

In the post below I stumbled upon a weird datum. Kuwait’s total fertility is now below 3. The average estimates seem to be ~2.5 or so. This surprised me, as my impression was that Gulf Arab petroleum based states tended to encourage pro-natalism. This was both a matter of ideology, and also because the small and wealthy native populations lived off rents, and had not had to modify their neo-medieval ideologies to foster productivity driven economic growth. But perhaps Kuwait is an anomaly? Well, it turns out that the Saudi fertility rate is now below 3 as well. Again, depending on which numbers you trust a value of ~2.5 seems plausible. In 1980, at the peak of OPEC’s power and a period when Saudi Arabia was flush with incredible per capita wealth the fertility rate was north of 7.0. But even in the mid-1990s Saudi Arabia’s fertility remained a robust 5.0. Obviously one has to account for the fact that some of the “Arab” nations are not very Arab. The UAE has huge South Asian and Persian populations, not to mention all other sorts. So its fertility of 1.80 can be chalked up to its unique demographics. But would you have guessed that Lebanon’s fertility rate is now the same as Finland’s?

Below the fold is a chart which shows the trends among Arab nations and Finland over the past 40 years. The shading of the bars is proportional to life expectancy.


Image Credit: Denise Chan

July 31, 2011

Probability of pregnancy by age

Filed under: Culture,Data Analysis,Fertility,GSS,Health,infertility — Razib Khan @ 1:25 pm

I just finished reading My Fertility Crisis, which is excerpted from a longer piece you can get on Kindle for $1.99. The author is a single woman in her early 40s who is going through IVF treatments, without success so far. She outlines the choices she made over her life which may have influenced her current situation.

After reading the piece I came back to an issue I’ve wrestled with before: it’s often really hard to find information on probability of pregnancy online in the form of charts. The reason is that there’s so much information, and much of it is skewed toward people who are undergoing treatment for infertility. But why look when you can generate your own visualization? I  found a pregnancy probability calculator online which I cross-validated with some of the literature. Here is the best case scenario for probability of pregnancy if you are trying in the natural fashion (the probabilities exclude women who are clinically infertile, which is a rather slippery category strongly dependent on age, so the older cohorts are probably much larger overestimates than the younger ones):

The main focus is really the ...

January 16, 2011

Which nation is the most pro-natalist?

Filed under: data,Data Analysis,Fertility,Teen Fertility — Razib Khan @ 3:05 pm

Poking around Google Data Explorer I reacquainted myself with an interesting fact: though the teen birth rate in Bangladesh is greater than that in Pakistan, the total fertility rate is far lower. The disjunction has emerged over the last generation, as Bangladesh’s TFR has dropped much faster than Pakistan’s. To the left you see a scatter plot, which shows teen fertility rates (age 15-19) as a function of total fertility rates. I’ve labeled a few nations, and also added the color coding by region. It is notable that the nations above the trend line seem to be Latin American, while those below are disproportionately Middle Eastern. That means that Latin American nations have higher teen fertility in relation to their total fertility, while Middle Eastern nations have lower teen fertility in relation to their total fertility. Sweden actually has a rather high fertility rate in relation to its teen birth rate. The expectation is generated by world wide patterns, so I thought I’d look more closely at the original data sets from the The World Bank. All the data is from 2008.  The teen birth rates are per 1,000 ...

August 21, 2010

“India’s” population bomb isn’t rocket science

Filed under: Culture,Data Analysis,Demographics,Fertility,India,Population — Razib Khan @ 6:59 pm

The New York Times has a piece up, Defusing India’s Population Time Bomb, which reiterates what I was trying to get at yesterday, India’s demographic problems are localized to particular regions, not the nation as a whole. First, let’s review the world’s population growth & fertility rates:

Now let’s focus on a few nations:


China’s coercive policy is often held up as a great success of the power of government to change from on high. But did you see the world population growth correction in the early 1960s? That was China. If you don’t know what was going on in China then, read books (hint: if you don’t know much about the history of China, you don’t know much about the history of the world). My point is that China’s solution was in part a reaction to a pro-natalist drive encouraged by one of the most powerful crazy men in the history of the world. On pure pragmatic grounds one may say that China had to do something, but their actions in the early 1980s did not occur in a vacuum, and were a consequence of a sequence of earlier events particular to that nation.

Contrast China with South Korea, a culturally similar nation, which went through decades of authoritarian rule, but never imposed coercive family planning policies of the sort common in the People’s Republic. Like Japan and Taiwan South Korea’s fertility and population growth rates declined naturally through economic development. With abundant human capital (high literacy) to start out with these nations replicated, and in some ways exceeded, the trajectory of the European demographic transition concomitant with an increase in economic productivity and urbanization. In fact, their fertility rates are lower than that of China, probably because they’re economically more advanced. If it wasn’t for China’s three decade long dance with crazy Communism the coercive policies in relation to reproduction may never have been necessary.

Economic development isn’t the only way to staunch population growth. Iran has taken a different, and less optimal, but still not grossly coercive, path. Because of the lack of economic opportunity in Iran’s society there was an understanding at both the commanding heights and the grassroots that large families were simply not sustainable, at least not using the quality of life which people had become used to in the 1970s as a reference point.

As I noted yesterday, the problem within India is that there is a wide region-to-region variation. The southern cone of India is already verging toward sub-replacement fertility. A major difference I see between China and India though is that the economically and socially most backward area is the cultural heart of the latter. There may be vague analogies to Italy, where Rome is a government town in the center, while northern Italy is the economic motive force, and southern Italy serves as a vote-bank which reliably backs the party which makes the biggest cash transfer promise. A big difference between Italy and India: the backward region is numerically dominant in India, while it is not in Italy.

Here are two bubble plots which show the divide in India. The size of the bubbles are proportion to the population size of the state. The two ones to the top left are Uttar Pradesh and Bihar.

The fact is that South Asia is low on the human capital scale:

800px-World_literacy_map_UN

The only long term solution is to leverage the fact that other parts of the world are higher up on the human capital ladder, and still producing innovation and generating new ways to increase productivity. Matt Yglesias has a post up about Japan, from which I got this chart:

TFPjapan-1

Because Japan’s population is shrinking its economy will decline over time. Additionally, because of the unfavorable demographics, with more older people than young workers, it will go through some decline in quality of life. But the average Japanese still consumes at a very high level, it’s not dystopia. Ultimately the Japanese are relying on innovation to buoy their economy. And that’s the real long term solution: without innovation we’re f**ked. Period. Demographic adjustments are really epiphenomena on the margins. That’s why the media can report on both sides of the ledger as if they are both positive and negative. It’s about quality of human capital and the innovation they’re producing, not the quantity of humans.

Image Credit: Wikimedia

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