You have probably seen (or participated in/judged) “gender reveal” parties in your social circles and online. I know I have, and and am always struck with how many people don’t realize that it’s not a strict 50/50 chance of getting a boy vs a girl. As demographers and evolutionary biologists know well, the natural baseline is tilted ever so slightly in favor of males at around 105 boys being born for every 100 girls. This indicator may seem pretty banal on surface level, but it reflects underlying patterns of maternal health, prenatal survival, and, in some contexts, gender discrimination. So, it is alarming when there are countries where this sex ratio at birth (SRB) is artificially skewed way past that level.
We have danced around the topic of sex ratios in China (and implications for marriage), and delved into son preference in India and Pakistan. Today, let’s face that head-on with the drivers and implications of a very skewed SRB. We go to Azerbaijan where it is the highest in the world at a whopping 111 boys for every 100 girls born.
Source: Pew Research Center (2022)
What causes this skew globally?
In 1990, Amartya Sen popularized the fact that there were 100 million “missing women” in the world due to gender-based discrimination. Updates since have found that number has kept climbing, reaching around 126 million million by 2010, and projected to peak near 150 million around 2035 before easing off, with China and India accounting for most of the deficit in women (I hate how that sounds, but here we are). There’s 2 main factors that drive this increase: postnatal excess female deaths (red line in the figure), and prenatal sex selection (blue line in the figure).
Soure: Bongaarts & Guilmoto (2015)
Spoiler alert: Eagle-eyed readers will notice that these two lines are headed in opposite directions. Prenatal sex selection is projected to keep shrinking as more countries complete the kind of transition we’ll see with Azerbaijan below. BUT, excess postnatal mortality, which has actually been the bigger driver the whole time, keeps climbing. So even as the sex-selection story (the whole subject of this piece) winds down globally, the fact of “missing women” doesn’t. It reverts to being a story less about who gets born, and more about HOW women who ARE born get treated over their life course. And that shows up in so many of the pieces we have discussed already on maternal mortality, child marriage, and sadly I suspect, more later down the road.
But what drives these drivers? It’s actually not terribly complicated, and the same three ingredients show up in nearly every affected country, in a framework laid out by demographer Christophe Guilmoto. First, a cultural preference for sons has to already exist. Second, fertility has to fall low enough that families can’t just keep having children until a son shows up (because plenty of societies have son preference and high fertility, and they never develop a skewed SRB, because parents simply have a fourth or fifth child instead of intervening.) Third, parents need access to the technology, mainly ultrasounds, that lets them find out a fetus’s sex early enough to act on it. The latter is likely the most critical in many contexts, because it provides the tools to actually act on son preference early on. Take any one of the three away, and the imbalance largely doesn’t happen. That said, you’ll see all three show up again, in slightly different combinations, in Azerbaijan’s own story below.
There is consistent empirical evidence to show that son-preference in societies leads to prenatal sex selection (and even female infanticide), leading to a shortfall in newborn girls. Life is not always rosy after birth, there is also evidence that corrosive gender discrimination affects women through their lifespan, leading to compounding neglect and excess mortality. This visual captures the nuances of the interconnected pathways between son preference and sex-selective abortion well:
Source: Pennington, Maudsley, Whitehead (2023)
What are the implications of this skew globally?
Here’s the thing about a skewed SRB: it doesn’t stay as a statistic in that year of excess or deficits in births. It ages. Every cohort of “extra” boys grows up, and roughly two decades later, tries to find a bride from a cohort of girls that was never born in equal numbers. Demographers call this the marriage squeeze, and we saw this in the China piece (where I mentioned a documentary that is quick to watch and revealing). The U.S. Census Bureau illustrates this beautifully with South Korea: the cohort born during Korea’s SRB peak (roughly 1990–2000) is now in its 20s, and the ratio of men aged 20–29 to women aged 15–24 sits at 1.39: a lopsided dating pool. Men in that generation face postponed marriage, marrying up in age, or not marrying at all. Azerbaijan’s is there too as a comparison for what’s coming down the pike.
Beyond the marriage squeeze, researchers have documented a grim list of downstream effects: bride trafficking and bride kidnapping, increases in gender-based violence and crime rates (particularly studied in China), and demand for “imported” brides across borders.
Get to the point already:What’s happening in Azerbaijan with the SRB?
Azerbaijan is one of the more head-scratching cases in this literature, and I mean that as a compliment. You will note that I struggled to find a lot of studies on SRB and Azerbaijan specifically, which means I go on random tangents. Apologies in advance.
Unlike India or China, where son preference has ancient, well-documented roots, Azerbaijan’s SRB was biologically normal until the 1980s (!) hovering around 105–107, same as everywhere else without intervention. Then something happened (any guesses what?) and the ratio climbed to 107 by 1990, crossed 110 by the early 1990s, and kept climbing to a peak somewhere in the range of 117–119 by the early-to-mid 2000s, depending on the dataset. It’s held stubbornly high since, easing only slowly. Over the 2000–2020 window as a whole, Pew’s analysis of UN data found Azerbaijan essentially tied with China for the most skewed sex ratio at birth in the world, averaging around 115. And because China’s ratio has come down faster in the years since, Azerbaijan is now frequently cited as currently the most skewed in the world.
Source: Tafuro and Guilmoto (2020)
So what happened in the 1990s? Azerbaijan (along with Armenia and Georgia) got hit with all three ingredients from that framework I mentioned at once: son preference that had been present all along but was latent without the means to act on it, a collapsing fertility rate (Azerbaijan’s TFR fell from 5.6 in 1961 to just 1.8 by 2001), and very very critically, new access to cheap, portable ultrasound machines after the fall of the Soviet Union, when import restrictions on the technology disappeared overnight.
The Guttmacher Institute’s analysis shows that a portion of that post-Soviet ultrasound supply is believed to have arrived via donations from each country’s diaspora communities abroad (more on that in a bit, you know I love a diaspora story, remember Somalia?) They find that Azerbaijan, Armenia, and Georgia all skewed sharply after 1991. But other former Soviet states with near-identical starting conditions (Moldova, Kazakhstan, Ukraine) never did. The leading hypothesis is that Azerbaijan and Armenia’s status as combatants in a “frozen war“ over Nagorno-Karabakh created a level of chronic insecurity, and diminished women’s bargaining power, that Moldova simply didn’t experience. I am not a political demographer so someone please jump in if there’s other updated evidence that I simply did not see - but it is on face value, a striking illustration of how conflict and NOT just poverty or culture in the abstract can be an active ingredient in prenatal discrimination.
There’s a lovely qualitative study from UNFPA that I enjoyed digging into: What struck me most was how consistently people reached for the same handful of images to explain son preference, almost regardless of age, region, or how educated they were. The parallels with the context I know the best (India), were strong.
Daughters came up again and again as temporary residents of their birth family: raised, loved, and then handed off to belong to someone else’s household once married, while sons were the ones who stayed rooted to the family line for life. One elderly man in a focus group reached for a well-worn local proverb to make the same point about cost rather than belonging — something to the effect of raising a daughter is like carrying a sack of salt, heavy and impossible to set down until she’s safely married off. Sons, by contrast, were repeatedly described in much more transactional, protective terms: the ones who would carry their parents’ coffin, defend the family’s honor, and serve in the army to protect the country itself.
And the education/wealth relationship isn’t the tidy “richer and more educated people select less” story you might expect. It’s curvilinear, with the highest SRB showing up among both the least and the most educated women, and among both the poorest and the richest households.
Finally, a small detail from that same fieldwork that’s stuck with me since I read it: men in the focus groups were already, back in 2012, working out loud through what would happen a generation later: reasoning that with so few girls being born relative to boys in their own community, Azerbaijani families would eventually have no choice but to look abroad for wives, and that this would come at a cost to the country’s own traditions and language, since it’s mothers who do most of that cultural transmission at home. They are basically predicting the marriage squeeze, years before most of the academic literature caught up to the same conclusion.
Birth orders, not so orderly
If there’s one pattern that shows up in every country, it’s this: sex selection concentrates at higher birth orders, and especially at the birth immediately following an existing daughter (or two). Families let the first birth “go to nature,” and only intervene once they haven’t gotten a son. I have boy/girl twins, and I cannot tell you how often I get people exclaim that I am so “lucky” I got both genders at once so I didn’t have to keep going. Really. I of course, have the choicest stuff to say back to them, don’t worry.
Azerbaijan follows this pattern exactly. Using decision-tree analysis of DHS data, researchers found the sex ratio is already elevated at first birth (113), suggesting some selection happens even before parents “need” a son. If the firstborn is a boy, the second birth’s ratio is normal. But if the firstborn is a girl, the second-birth ratio stays elevated at 113; and if the first two are both girls, the third birth’s ratio jumps to 128. Yes this research is outdated, but I couldn’t find an updated decision tree and didn’t have time to make one (sorry!) BTW I know I have Guttmacher friends reading this - a request to please update this analysis!
Source: Guttmacher (2013)
By contrast, Moldova (this study’s “control” country), is similar in every other respect and shows no meaningful parity effect at all: 102 if the firstborn is a boy, 108 if a girl. It’s a clean natural experiment for what son preference plus access to ultrasound actually looks like in the data, versus its absence. The same signature shows up thousands of miles away in South Korea’s 1991 and 2003 fertility surveys: among women who stated they “must have a son,” the sex ratio for second-and-higher births was a roughly normal 105 if a previous child was already a boy, but a jaw-dropping 194 if all previous children were girls.
What does this mean for Azerbaijan?
Zooming back into Azerbaijan specifically: researchers estimate that in 2010 alone, roughly 8,381 female births went “missing“ in the country due to sex-selective abortion: nearly 10% of the number of girls you’d expect to be born that year. Across Azerbaijan, Armenia, and the Western Balkans combined, UNFPA estimates over 171,000 girls “missing” as a result of these practices. And their forward-looking model isn’t reassuring: if the current disparity in Azerbaijan simply holds steady (never mind worsens), up to 15,000 more boys than girls could be born every single year by 2050. It’s the same marriage squeeze Korea already lived through, except Azerbaijan’s cohort is still working its way toward marriageable age.
And there is a tendency to focus on marriage. BUT there’s a real, embodied cost to the women in the middle of all this. The UNFPA fieldwork is hard to sit with in places. Interviewers heard versions of the same story surface across multiple regions: a woman several pregnancies deep, each ultrasound bringing the same disappointing news, her in-laws’ patience visibly thinning with every daughter sometimes across five, six, seven pregnancies before a son finally arrived, sometimes not at all. One account described a sister-in-law who endured eight pregnancies after her first two sons, was repeatedly threatened with being sent back to her own family if a scan came back female, and ultimately needed a hysterectomy after so many terminations. This is, at its core, a maternal health story as much as a demographic one. The closer a woman gets to her family’s “acceptable” number of daughters, the more medically dangerous the pressure to keep trying becomes. This could be a hidden aspect of maternal mortality that we covered in Sierra Leone, Australia, and the USA.
And the diaspora(?)
I could not find a single published academic study measuring sex ratios at birth specifically within the Azerbaijani diaspora. Not in Russia (over 2 million Azerbaijanis), not in Turkey (~1 million), not in the US (~400,000) or Europe (~300,000). That likely reflects how much smaller and more dispersed the Azerbaijani diaspora is compared to India’s or China’s, which have drawn far more research attention.
But the broader diaspora literature on son preference is worth borrowing from, because it consistently shows the practice travels with people rather than staying behind (the diffusion theory, for better or worse) A 2025 population-based study of over 2 million Australian births found the SRB for children born to Chinese- and Indian-born mothers was skewed well above natural levels, and got sharply worse at higher parities: 1.09 at second birth for Chinese-born mothers, jumping to 1.34 at third birth if the first two children were girls, with a similar pattern for Indian-born mothers. Even more striking: a study spanning the US, UK, Canada, and Australia found that for Indian-origin families having a third child after two daughters, the sex ratio in the diaspora was often more skewed than in India itself: 520 girls per 1,000 boys in Canada and 653 in Australia, versus 769 in India in the same year (!!!!!) Migration to a high-income, low-son-preference country didn’t dilute the practice. For some families it appears to have concentrated it, perhaps because access to prenatal ultrasound and abortion services is easier, not harder, once abroad.
There’s one more thread worth pulling on the diaspora question, and it’s more historical than statistical: some of the post-Soviet ultrasound machines that made sex-selective abortion feasible across the South Caucasus in the first place are believed to have arrived through donations from diaspora communities abroad, once import restrictions lifted after 1991 though the researchers are careful to note there’s no direct evidence tying those specific donations to sex-selection outcomes. Still, it’s a reminder that “diaspora” doesn’t only show up in this story as a downstream population that might replicate the practice abroad, in Azerbaijan’s case, it may also have been part of the original supply chain of the technology that enabled it at home.
What’s wealth got to do with it (got to do with it)
Azerbaijan’s curvilinear education/wealth relationship makes more sense once you see South Korea’s data. A 1981–2005 analysis of Korean birth records found that in the early 1980s, when sex-selection technology first arrived, the highest male-birth ratios showed up among Seoul’s most educated, highest-status mothers, i.e. the “pioneers.” But by the SRB’s peak in the early 1990s, that pattern had completely reversed: it was now rural, less-educated, working-class mothers showing the highest ratios, as the technology diffused outward and the early adopters had already started pulling back. If Azerbaijan is somewhere in the middle of that same diffusion curve, its messy, non-linear education pattern may just be a snapshot mid-transition, rather than a different story.
What’s actually worked (and what hasn’t)
Sadly, not much. India’s 1994 ban on doctors disclosing a fetus’s sex has been enforced in a handful of high-profile prosecutions but has done little to stop the practice. Physicians just got better at hinting. Azerbaijan’s own, quieter version fares no better: the Ministry of Health recommends doctors withhold fetal sex during scans, but the UNFPA report shows that fieldworkers found plenty just weren’t following it. Disclosure bans are only as strong as the person holding the probe.
What shows more promise are interventions aimed indirectly at raising the social value of daughters, though the evidence base is still thin. Azerbaijan’s current efforts sit in this camp: UNFPA-backed “Fathers’ Schools” running across Azerbaijan, Armenia, and Georgia work directly with men to challenge the belief that a family isn’t complete without a son, and neighboring Albania has run a public campaign built around the disarmingly simple line, “next time, I hope it’s a girl.” I think often about son preference with respect to population aging/fertility decline. We know that son preference exists in some cultures because it is expected that sons will care for their parents in old age. But what we are actually seeing, is that it’s the daughters that are stepping in. So, will population aging reverse some of this son preference in light of reality vs. expectation?
Looking ahead
Formal projections of sex ratios through 2100 place Azerbaijan among the countries currently in the plateau-to-decline stage of what demographers call the sex ratio transition, alongside Armenia, China, India, and Vietnam, with a projected end date for the transition sometime in the 2030s, albeit with real uncertainty around that estimate.
What’s interesting is how differently this has played out for Azerbaijan’s own neighbors. Georgia was hit by the exact same post-Soviet shock and access to ultrasound, arguably an even more acute conflict environment, and has already largely completed its transition, with its SRB back near the natural range (107–108) as of the late 2010s. If Korea’s norms-vs-policy split is any guide, the difference probably has less to do with GDP or education levels, where the two countries look similar, and more to do with how quickly underlying beliefs about needing a son have actually shifted. This is a much harder thing to legislate or fund your way toward than a disclosure ban or a cash transfer.
Whatever happens to Azerbaijan’s SRB from here, the more sobering point is this: girls and women are still dying. And the cohort that will feel these effects most acutely (the boys born during the 2000s peak) are already teenagers and young adults today. Even a full, immediate normalization of the sex ratio at birth wouldn’t undo the demographic math that’s already been set in motion. The next couple of decades in Azerbaijan will show us, in real time, whether a country can build back a “normal” birth sex ratio faster than its own missing generation of daughters grows into the marriage market it left behind.
The Food!
We made one of the most delightful looking dishes, but the taste was so-so (I bought the wrong kind of mutton, so it was rubbery. It likely is delicious). We made shah plov: a mutton biryani wrapped in lavash, and mangal salati: roasted veggies turned into a dip. I recognize I need to work on my photography skills because what I ended up taking is overwhelmed by the steam and looks like it was shot on a Nokia. We were too consumed with all the World Cup happenings to listen to music or research, but the kids promise they will get back on the wagon after July 19. I however, cannot promise I will improve on my picture-taking skills.
