Tuesday, April 16, 2024

I have one partner now with three kids. He is transmasc, and he’s radical about the way he raises them. They’re radically home-schooled. They’re 17 and nonbinary, 6 and 5. They know everything in age-appropriate ways. They’ve seen their mommy undergo the transmasc experience

Lessons From a 20-Person Polycule. Interviews by Daniel Bergner, photographs by Anne Vetter. The New York Times, Apr 2024. https://www.nytimes.com/interactive/2024/04/15/magazine/polycule-polyamory-boston.html


Ann: I have one partner now with three kids. He is transmasc, and he’s radical about the way he raises them. They’re radically home-schooled. They’re 17 and nonbinary, 6 and 5. They know everything in age-appropriate ways. They’ve seen their mommy undergo the transmasc experience, seen their mom become who they really are.

I was up late last night with him in a hotel room, and the 17-year-old was in the room snoozing, so we just sat on the bathroom floor chatting about our relationship all night, and while that was happening my husband was texting to say, Oh, I got a last-minute match, so I’m going to meet this girl for a date. And then I get a text while we were still on the bathroom floor vibing, it was 4 in the morning, and he said, We had a great date, a great connection, she’s looking for friends with benefits, we had sex. And I was smiling. You know you’re really poly when you’re with one of your partners talking about how much you love each other and you’re so happy your husband had this awesome night. Of course, I experience pangs of jealousy, but there are these moments, these gems, of being so happy for someone else’s happiness.

Wednesday, February 28, 2024

'Soberising' the enemy with a nuke or two, avoiding escalation — Leaked Russian military files reveal criteria for nuclear tactical strikes

Leaked Russian military files reveal criteria for nuclear strike. Max Seddon and Chris Cook in London

https://www.ft.com/content/f18e6e1f-5c3d-4554-aee5-50a730b306b7

Doctrine for tactical nuclear weapons outlined in training scenarios for an invasion by China

Vladimir Putin’s forces have rehearsed using tactical nuclear weapons at an early stage of conflict with a major world power, according to leaked Russian military files that include training scenarios for an invasion by China.

The classified papers, seen by the Financial Times, describe a threshold for using tactical nuclear weapons that is lower than Russia has ever publicly admitted, according to experts who reviewed and verified the documents.

The cache consists of 29 secret Russian military files drawn up between 2008 and 2014, including scenarios for war-gaming and presentations for naval officers, which discuss operating principles for the use of nuclear weapons.

Criteria for a potential nuclear response range from an enemy incursion on Russian territory to more specific triggers, such as the destruction of 20 per cent of Russia’s strategic ballistic missile submarines.

“This is the first time that we have seen documents like this reported in the public domain,” said Alexander Gabuev, director of the Carnegie Russia Eurasia Center in Berlin. “They show that the operational threshold for using nuclear weapons is pretty low if the desired result can’t be achieved through conventional means.”

Russia’s tactical nuclear weapons, which can be delivered by land or sea-launched missiles or from aircraft, are designed for limited battlefield use in Europe and Asia, as opposed to the larger “strategic” weapons intended to target the US. Modern tactical warheads can still release significantly more energy than the weapons dropped on Nagasaki and Hiroshima in 1945.

Although the files date back 10 years and more, experts claim they remain relevant to current Russian military doctrine. The documents were shown to the FT by western sources.

The defensive plans expose deeply held suspicions of China among Moscow’s security elite even as Putin began forging an alliance with Beijing, which as early as 2001 included a nuclear no-first-strike agreement.

In the years since, Russia and China have deepened their partnership, particularly since Xi Jinping took power in Beijing in 2012. The war in Ukraine has cemented Russia’s status as a junior partner in their relationship, with China throwing Moscow a vital economic lifeline to help stave off western sanctions.

Yet even as the countries became closer, the training materials show Russia’s eastern military district was rehearsing multiple scenarios depicting a Chinese invasion.

The exercises offer a rare insight into how Russia views its nuclear arsenal as a cornerstone of its defence policy — and how it trains forces to be able to carry out a nuclear first strike in some battlefield conditions.

One exercise outlining a hypothetical attack by China notes that Russia, dubbed the “Northern Federation” for the purpose of the war game, could respond with a tactical nuclear strike in order to stop “the South” from advancing with a second wave of invading forces.

“The order has been given by the commander-in-chief . . . to use nuclear weapons . . . in the event the enemy deploys second-echelon units and the South threatens to attack further in the direction of the main strike,” the document said.

China’s foreign ministry denied there were any grounds for suspicion of Moscow. “The Treaty of Good-Neighborliness, Friendship and Cooperation between China and Russia has legally established the concept of eternal friendship and non-enmity between the two countries,” a spokesperson said. “The ‘threat theory’ has no market in China and Russia.”

Putin’s spokesperson said on Wednesday: “The main thing is that the threshold for the use of nuclear weapons is absolutely transparent and is spelled out in the doctrine. As for the documents mentioned, we strongly doubt their authenticity.”

A separate training presentation for naval officers, unrelated to the China war games, outlines broader criteria for a potential nuclear strike, including an enemy landing on Russian territory, the defeat of units responsible for securing border areas, or an imminent enemy attack using conventional weapons.

The slides summarise the threshold as a combination of factors where losses suffered by Russian forces “would irrevocably lead to their failure to stop major enemy aggression”, a “critical situation for the state security of Russia”.

Other potential conditions include the destruction of 20 per cent of Russia’s strategic ballistic missile submarines, 30 per cent of its nuclear-powered attack submarines, three or more cruisers, three airfields, or a simultaneous hit on main and reserve coastal command centres.

Russia’s military is also expected to be able to use tactical nuclear weapons for a broad array of goals, including “containing states from using aggression […] or escalating military conflicts”, “stopping aggression”, preventing Russian forces from losing battles or territory, and making Russia’s navy “more effective”.

Putin said last June that he felt “negatively” about using tactical nuclear strikes, but then boasted that Russia had a larger non-strategic arsenal than Nato countries. “Screw them, you know, as people say,” Putin said. The US has estimated Russia has at least 2,000 such weapons.

Putin said last year that Russian nuclear doctrine allowed two possible thresholds for using nuclear weapons: retaliation against a first nuclear strike by an enemy, and if “the very existence of Russia as a state comes under threat even if conventional weapons are used”.

But Putin himself added that neither criteria was likely to be met, and dismissed public calls from hardliners to lower the threshold.

The materials are aimed at training Russian units for situations in which the country might want the ability to use nuclear weapons, said Jack Watling, a senior research fellow for land warfare at the Royal United Services Institute, rather than setting out a rule book for their use.

“At this level, the requirement is for units to maintain — over the course of a conflict — the credible option for policymakers to employ nuclear weapons,” Watling added. “This would be a political decision.”

While Moscow has drawn close to Beijing since the war games and moved forces from the east to Ukraine, it has continued to build up its eastern defences. “Russia is continuing to reinforce and exercise its nuclear-capable missiles in the Far East near its border with China,” said William Alberque, director of strategy, technology and arms control at the International Institute for Strategic Studies. “A lot of these systems only have the range to strike China.”

Russia was still behaving in accordance with the “theory of use” of nuclear weapons set out in the documents, Alberque said. “We have not seen a fundamental rethink,” he said, adding that Russia is probably concerned that China may seek to take advantage of Moscow being distracted “to push the Russians out of Central Asia”.

The documents reflect patterns seen in exercises the Russian military held regularly before and since Putin’s invasion of Ukraine in 2022. Alberque, who previously worked for Nato and the US defence department on arms control, pointed to examples of Russian exercises held in June and November last year using nuclear-capable Iskander missiles in two regions bordering China.

While Russia’s president has the sole authority to launch a first nuclear strike, the low threshold for tactical nuclear use set out in the documents conforms with a doctrine some western observers refer to as “escalating to de-escalate”.

Under this strategy a tactical weapon could be used to try to prevent Russia from becoming embroiled in a sprawling war, particularly one in which the US might intervene. Using what it calls “fear inducement”, Moscow would seek to end the conflict on its own terms by shocking the country’s adversary with the early use of a small nuclear weapon — or securing a settlement through the threat to do so.

“They talk about ‘soberising’ their adversaries — knocking them out of the drunkenness of their early victories by introducing nuclear weapons,” said Alberque. “The best way that they think they can do that is to use what they call a lower ‘dosage’ of nuclear weapons at a much lower level of combat to prevent escalation.”

Ukrainian officials argued that Putin’s nuclear threats convinced US and other allies not to arm Kyiv more decisively early in the conflict, when advanced Nato weaponry could have turned the tide in Ukraine’s favour.

Alberque said Russia would probably have a higher threshold for using tactical nuclear weapons against Ukraine, which does not have its own nuclear capability or the ability to launch a ground invasion on the same scale, than against China or the US.

Russian leaders believe that, whereas a nuclear strike against China or the US could be “soberising”, a nuclear strike on Ukraine would be likely to escalate the conflict and lead to direct intervention by the US or UK, Alberque said. “That is absolutely the last thing Putin wants.”


Additional reporting by Joe Leahy in Beijing


Friday, February 2, 2024

Unelected elites such as lobbyists, civil servants, journalists, and the like overestimate a lot how much the general population agrees with their own political views

The people think what I think: False consensus and unelected elite misperception of public opinion. Alexander C. Furnas, Timothy M. LaPira. American J of Pol Sci, January 24 2024. https://doi.org/10.1111/ajps.12833


Abstract: Political elites must know and rely faithfully on the public will to be democratically responsive. Recent work on elite perceptions of public opinion shows that reelection-motivated politicians systematically misperceive the opinions of their constituents to be more conservative than they are. We extend this work to a larger and broader set of unelected political elites such as lobbyists, civil servants, journalists, and the like, and report alternative empirical findings. These unelected elites hold similarly inaccurate perceptions about public opinion, though not in a single ideological direction. We find this elite population exhibits egocentrism bias, rather than partisan confirmation bias, as their perceptions about others' opinions systematically correspond to their own policy preferences. Thus, we document a remarkably consistent false consensus effect among unelected political elites, which holds across subsamples by party, occupation, professional relevance of party affiliation, and trust in party-aligned information sources.


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Our tests of competing explanations for these misperceptions are robust and consistent: Unelected political elites demonstrate a false consensus effect in their estimates of public opinion. Simply, elites believe that the policies they support are more popular among the general public than they actually are, and that the policies they oppose are less popular than they actually are. This relationship is true regardless of the elite's party identification, professional specialization, or information environment.


Monday, January 15, 2024

Treatment of the Taiwanese in Chinese Communist Documents and Statements: 1928-1943

The Chinese Communist Party and the Status of Taiwan, 1928-1943. Frank S. T. Hsiao and Lawrence R. Sullivan. Pacific Affairs, Vol. 52, No. 3 (Autumn, 1979), pp. 446-467. Pacific Affairs, University of British Columbia. http://www.jstor.org/stable/2757657

Extracts.

[...]

Treatment of the Taiwanese in Chinese Communist Documents and Statements: 1928-1943

At the CCP's Sixth National Congress, held in Moscow in 1928, the Chinese Communists took the first step toward accepting Taiwan's future political autonomy by acknowledging that the Taiwanese were ethnically separate from the Han. This is evident in their explicit reference to the Taiwanese as a distinct "nationality," and, on occasion, as a separate "race" (zhongzu) or "stock" (zongzu). (Further discussion of terminological differences is presented below). The first CCP statement referring to Taiwanese focused on the "Taiwanese in Fukien." According to the Sixth Congress' "Resolution on the Nationality Problem," the Sixth National Congress of the Chinese Communist Party considers that the problems of minority nationalities within Chinese territory (Mongols and Mohammedans in the North, Koreans in Manchuria, Taiwanese in Fukien, the aborigines of Miao and Li nationalities in the South, and in Sinkiang [Uighur] and Tibetan nationalities) have important significance [emphasis added]. In other words, the "Taiwanese in Fukien" were considered to be a "minority nationality" and not simply members of one provincial group residing in another province. More importantly, the Taiwanese were grouped with other minority nationalities—Mongols, Mohammedans, Miao, Uighurs, etc.—which had maintained their ethnic identity throughout the dynastic era and had been able to assert some political autonomy vis-à-vis the imperial court. This position of the Sixth Congress was reiterated in the same year by the Fifth National Congress of the Chinese Communist Youth League, which in its regulations noted that the "minority nationalities" in China included "Mongols, Koreans, Taiwanese, Annamese, etc.," and urged that local organs form national minority committees. Two years later in Kiangsi, the "Draft Constitution of the China Soviet Republic," adopted by the First All-China Soviet Congress (November 7, 1931), extended constitutional rights to these same minority nationalities. According to Item 4 of this document, all races, that is the "Han, Manchu, Mongol, Mohammedan, Tibetan, Miao, Li and also the Taiwanese, Koreans, and Annamese who reside in China, are equal under the laws of Soviet China [emphasis added]." 7 Taiwanese were seen not as Han but as a different "nationality" and even "race," who like the Koreans and the Annamese, but unlike the other minorities, came from a homeland separate from China.8 This view is strengthened by the fact that the CCP never referred to the Taiwanese as "brethren" (dixiong), or "the offspring of the Yellow Emperor," or "compatriots" (tongbao), who would de facto belong to the Han after they return to China. Indeed, a 1928 Central Committee Notice, while calling for the recovery from Japan of sovereignty over Shantung and Manchuria, failed to mention a similar goal for Taiwan in its seventeen "general goals of the present mass movement." Since the ideological perspectives of the early Chinese Communist elite were heavily influenced by an anti-Japanese (as well as an anti-Western) nationalism born out of the May Fourth Movement, this exclusion of Taiwan from recoverable sovereign territory of China is revealing.

Mao Tse-tung's earliest comments on the Taiwanese came in his January 1934 "Report of the China Soviet Republic Central Executive Committee and the People's Committee to the Second All-China Soviet Congress." Commenting on various provisions in the 1931 Constitution, he said:

"Item 15 of the Draft Constitution of Soviet China has the following statement: To every nationality in China who is persecuted because of revolutionary acts and to the revolutionary warriors of the whole world, the Chinese Soviet Government grants the right of their being protected in Soviet areas, and assists them in renewing their struggle until a total victory of the revolutionary movement for their nationality and nation has been achieved.

In the Soviet areas, many revolutionary comrades from Korea, Taiwan, and Annam are residing. In the First All-China Soviet Congress, representatives of Korea had attended. In the present Congress, there are a few representatives from Korea, Taiwan, and Annam. This proves that this Declaration of the Soviet is a correct one." 10

Mao not only reaffirmed the Chinese Communist position that Taiwanese residing outside Taiwan and in China were a "minority nationality," but also implied CCP recognition and support of an independent Taiwan national liberation movement, which would be united in a joint effort with the Chinese movement, but with a different purpose, i.e., the establishment of an independent state similar to other Japanese colonies, such as Korea.

A year later, Mao and P'eng Teh-huai manifestly dissociated Taiwan's political movement from China by incorporating it into the anti-imperialist revolution led by the Japanese Communist Party.

According to the "Resolution on the Current Political Situation and the Party's Responsibility," passed at a meeting of the CCP Central Political Bureau on 25 December 1935, and signed by P'eng and Mao:

"Under the powerful leadership of the Japanese Communist Party, the Japanese workers and peasants and the oppressed nationalities (Korea, Taiwan) are preparing great efforts in struggling to defeat Japanese Imperialism and to establish a Soviet Japan. This is to unite the Chinese revolution and Japanese revolution on the basis of the common targets of 'defeating Japanese imperialism.' The Japanese revolutionary people are a powerful helper of the Chinese revolutionary people." 11

Here Taiwanese were not considered an integral part of the "Chinese revolutionary people," but were treated as a people whose natural political role was to fight alongside the "Japanese workers and peasants" in establishing a Soviet Japan. Whether Mao and P'eng expected the Taiwanese (and Koreans) formally to join a newly-created Soviet Japan is unclear from this resolution. But nowhere in this or other documents examined by the authors did CCP leaders suggest that the Taiwanese should fight to return to their "motherland" and join Soviet China—a point they would not make until after 1943.

The independent character afforded the Taiwanese national liberation struggle by the CCP is most clearly stated in materials available from the period 1937 to 1941. At this time, when Mao Tse-tung stressed the "internationalist" character of the Chinese revolution, official decisions of Party organs and personal statements by CCP leaders point to Communist agreement that in the anti-Japanese struggle Taiwan possessed an independent political status. For instance, Mao's October 1938 Political Report "On the New Stage—the New Stage of Development in the Anti-Japanese National War and the Anti-Japanese National United Front," given to the CCP's Sixth Plenary Session of the Sixth National Congress, extended independence to the movements of various "oppressed nationalities of Korea, Taiwan, etc." by advocating that they join the Chinese nation in common action against Japanese imperialism. 13

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Notes

7 Item 14, however, asserts ". . . the right of self determination of the national minorities in China, their right to complete separation from China, and to the formation of an independent state for each national minority. All Mongolians, Tibetans, Miao, Yao, Koreans and others living on the territory of China shall enjoy the full right to self determination, i.e., they may either join the Union of Chinese Soviets or secede from it and form their own state as they may prefer. The Soviet regime of China will do its utmost to assist the national minorities in liberating themselves from the yoke of imperialists, the KMT militarists, t'u-ssu [native officials], the princes, lamas and others, and in achieving complete freedom and autonomy. The Soviet regime must encourage the development of the national cultures and the national languages of these peoples." Unlike Item 4, Taiwanese were not mentioned here, nor were the Manchus and Annamese. This may have been simply an oversight by the drafters of this constitution. On the other hand, since very few Taiwanese resided on China's mainland (mostly in Fukien, which was not a major part of Soviet China), and unlike the Koreans, which numbered 700,000 in 1934 (see Japan-Manchoukuo Year Book 1937, p. 48), perhaps the CCP logically excluded Taiwanese from a provision, borrowed from the U.S.S.R., which granted rights of secession, or alter- natively, created autonomous areas. Such a provision would not have been applicable to those groups which were not considered a minority within the existing political boundaries of China.

8 Throughout CCP documents from this period the Taiwanese are consistently grouped with the Koreans and Annamese. There are several possible reasons for this pattern. One is that the Taiwanese shared with the Koreans and Annamese a common bond to Chinese culture and a past inclusion in the Chinese empire at different points in history. A second is that all three areas were colonies of foreign powers which, as we shall argue below, led the CCP to grant them greater political autonomy than the minority nationalities within China, which although non- Chinese were also non-colonized peoples. A third is that Taiwan's experience with Japan made the Taiwanese less "Chinese" and more like the Koreans and Vietnamese, who combined Chinese cultural influence with their own unique identity. See, John K. Fairbank, ed., The Chinese World Order (Cambridge, MA: Harvard University Press, 1968).

 

Friday, January 5, 2024

People self-servingly inflate the moral value of randomly assigned personality traits they believe they possess

People self-servingly inflate the moral value of randomly assigned personality traits they believe they possess. Andrew J. Vonasch, Bradley A. Tookey. Journal of Experimental Social Psychology, Volume 112, May 2024, 104580. https://www.sciencedirect.com/science/article/pii/S0022103123001373

Abstract: Are people self-serving when moralizing personality traits? Past research has used cross sectional methods incapable of establishing causality, but the present research used experimental methods to test this. Indeed, two experiments (N = 669) show that people self-servingly inflate the moral value of randomly assigned personality traits they believe they possess, and even judge other people who share those same traits as more moral, warm, and competent than those who do not. We explain various methodological challenges overcome in conducting this research, and discuss implications for both psychology and philosophy.


Thursday, January 4, 2024

Reproductive Strategies and Romantic Love in Early Modern Europe

Reproductive Strategies and Romantic Love in Early Modern Europe. Mauricio de Jesus Dias Martins & Nicolas Baumard. Archives of Sexual Behavior, December 26 2023. https://link.springer.com/article/10.1007/s10508-023-02759-4

Abstract: In Western Europe, the Early Modern Period is characterized by the rise of tenderness in romantic relationships and the emergence of companionate marriage. Despite a long research tradition, the origins of these social changes remain elusive. In this paper, we build on recent advances in behavioral sciences, showing that romantic emotional investment, which is more culturally variable than sexual attraction, enhances the cohesion of long-term relationships and increases investment in children. Importantly, this long-term strategy is considered especially advantageous when living standards are high. Here, we investigate the relationship between living standards, the emotional components of love expressed in fiction work, and behavioral outcomes related to pair bonding, such as nuptial and fertility rates. We developed natural language processing measures of “emotional investment” (tenderness) and “attraction” (passion) and computed romantic love in English plays (N = 847) as a ratio between the two. We found that living standards generally predicted and temporally preceded variations of romantic love in the Early Modern Period. Furthermore, romantic love preceded an increase in nuptial rates and a decrease in births per marriage. This suggests that increasing living standards in the Early Modern Period may have contributed to the emergence of modern romantic culture.


Genetic variants underlying human bisexual behavior are reproductively advantageous

Genetic variants underlying human bisexual behavior are reproductively advantageous. Siliang Song & Jianzhi Zhang. Science Advances, Jan 3 2024. Vol 10, Issue 1. https://www.science.org/doi/10.1126/sciadv.adj6958


Abstract: Because human same-sex sexual behavior (SSB) is heritable and leads to fewer offspring, how SSB-associated alleles have persisted and whether they will remain in human populations are of interest. Using the UK Biobank, we address these questions separately for bisexual behavior (BSB) and exclusive SSB (eSSB) after confirming their genetic distinction. We discover that male BSB is genetically positively correlated with the number of offspring. This unexpected phenomenon is attributable to the horizontal pleiotropy of male risk-taking behavior–associated alleles because male risk-taking behavior is genetically positively correlated with both BSB and the number of offspring and because genetically controlling male risk-taking behavior abolishes the genetic correlation between male BSB and the number of offspring. By contrast, eSSB is genetically negatively correlated with the number of offspring. Our results suggest that male BSB–associated alleles are likely reproductively advantageous, which may explain their past persistence and predict their future maintenance, and that eSSB-associated alleles are likely being selected against at present.


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Popular press:

Risk-Taking Behavior Linked to Persistence of Male Bisexuality Genes

Summary: A new study sheds light on the persistence of genes associated with male bisexuality in the human genome. The research suggests that these genes are linked to risk-taking behavior, which confers reproductive benefits to heterosexual men carrying them.

By analyzing data from over 450,000 participants, the study found that risk-takers tend to father more children and are more likely to carry the genetic variants linked to bisexuality. This indicates that the reproductive advantage of these genes is a byproduct of the advantage of risk-taking behavior.


Key Facts:

Male heterosexuals carrying genetic variants associated with bisexuality father more children on average.

Risk-taking behavior, including unprotected sex and promiscuity, may be the underlying cause of this reproductive advantage.

The study distinguishes between genetic variants associated with bisexual behavior and exclusive same-sex behavior, with the former conferring reproductive benefits while the latter leads to fewer children over time.

Source: University of Michigan


Because same-sex sexual behavior does not result in offspring, evolutionary biologists have long wondered how the genes associated with this behavior have persisted in the human genome, and whether they will remain in the future.

A new University of Michigan-led study, scheduled for publication Jan. 3 in the journal Science Advances, suggests that part of the explanation—specifically for male bisexuals—has to do with risk-taking behavior.

The U-M researchers analyzed data from more than 450,000 participants of European ancestry in the United Kingdom’s Biobank database of genetic and health information. Participants responded to a questionnaire that included the question, “Would you describe yourself as someone who takes risks?”

The U-M analysis revealed that male heterosexuals who carry the genetic variants associated with bisexual behavior, which are known as BSB-associated alleles, father more children than average. Furthermore, men who describe themselves as risk-takers tend to have more children and are more likely to carry BSB-associated alleles.

However, the authors stress that their study looks at the genetic underpinnings of same-sex sexual behavior and not the behaviors themselves, which are affected by both genetic and environmental factors.

In fact, the proportion of UK Biobank participants reporting same-sex sexual behavior has been on the rise in recent decades, likely due to growing societal openness toward it, according to the researchers.

In addition, the authors say their new results “predominantly contribute to the diversity, richness, and better understanding of human sexuality. They are not, in any way, intended to suggest or endorse discrimination on the basis of sexual behavior,” they wrote.

The new study is a follow-up to one published in May in Proceedings of the National Academy of Sciences by Song and Zhang. That study also sought to explain the persistence of genetic variants associated with same-sex sexual behavior.

In 2021, Australian biologist Brendan Zietsch and colleagues presented evidence that heterosexuals carrying same-sex-associated alleles have more sexual partners than those not carrying the variants. This could confer a genetic advantage, the authors suggested, because more sexual partners could translate into more children.

In their PNAS study, which also relied on UK Biobank data, Zhang and Song showed that while the mechanism proposed by Zietsch likely worked in pre-modern societies, it is not active today because the widespread use of contraception has decoupled the number of offspring from the number of sexual partners in heterosexuals.

The findings presented in that PNAS paper led Zhang and Song to search for other potential mechanisms for the genetic maintenance of human same-sex behavior.