Today, this mystery could be slowly unraveling. Research from a genome-wide association study (GWAS) provides insights into the biological substrate of sexual orientation. In a controversial twist, it could even lead to unprecedented control given to prospective parents in deciding the sexual preferences of future children.
In October 2018, geneticist Andrea Ganna and his team at the Broad Institute reported that their review of markers across the entire genome of more than 493,000 test participants identified 4 genome-wide significant loci for homosexual behavior, with many more loci identified for partner count (meaning lifetime number of sexual partners) in heterosexuals. These results led researchers to estimate that 8-20% of variation in non-heterosexual behavior could be attributed to common genetic variants (those most likely to be detected through GWAS) found in this study. Some these genes display curious overlap with others that affect biological processes such as smell and hormone production, hinting at complex cross-genome relationships between sexual preference and other phenotypes. Previous twin and family studies had already suggested that about 40 percent of our sexual orientation is genetically heritable.
The significance of these results isn’t their confirmation of a genetically heritable component to homosexuality, but rather their identification of some of the specific gene variants involved. Scientists need to know which variants, or SNPs (single-nucleotide polymorphisms) are associated with which phenotypic traits to employ such technologies as PGD (preimplantation genetic diagnosis) and gene editing to alter the genetic makeup of future children. Identifying the SNPs associated with homosexual behavior means that manipulating the genetics of sexual orientation could one day become possible.
While this may seem futuristic, many countries are already edging towards embracing gene editing as a tool for altering the human blueprint. With no law prohibiting selection against or for specific sexual preferences yet in place, it remains possible that prospective parents may one day be able to choose or alter a future child’s sexual preferences.
Another place this could have a significant impact is China, where heavy government investment under the current 5-year plan and low barriers to entry have produced a flourishing biotechnology industry. China is already home to more than 10 genome-sequencing companies, one of which, the Beijing Genomics Institute, is the world’s largest. China is seen as a future site for the adoption of cutting-edge gene therapy techniques, even at a time when deliberation over important ethical qualms slows progress in many other countries. An example can be found in the palpable enthusiasm shown towards gene editing by Chinese firms, with one company already emphasizing its vision to “make human beings more beautiful and healthier” using these technologies.
With strong growth in preimplantation genetic diagnosis procedures and no laws directly prohibiting selection of sexual orientation, it’s possible that Chinese parents could soon begin deciding their child’s likely sexual preferences. The implications of this lie deep within the cultural context, as here homosexuality was banned for most of the 20th century. After legalization in 1997, it was finally removed from the official list of mental illnesses in 2001. Still, many taboos against homosexuals remain, and the status of LGBT culture is semi-underground.
For some in China’s gay community, the possibility that parents might soon be able to manipulate genetic orientation and alter an embryo so that it is less likely to result in a homosexual child is deeply concerning.
“I think that this tech will make more people consider homosexuality a mental illness,” said Harry Zhu, former legal team head at the Beijing LGBT Center. To Zhu, there is little question that selection against homosexuality, if offered as a service by the consumer genomics industry, would see widespread adoption by parents. “Maybe they are okay with a homosexual child,” he suggested. “But if you give them the opportunity to choose, they are more likely to choose a heterosexual kid.”
Zhu is unsure whether the ability to select a future child’s sexual orientation would lead to discrimination. Indeed, increased public awareness of the genetic component to homosexuality could feasibly engender sympathy by showing homosexuals to be acting partly on biological predispositions, rather than merely making ‘bad choices,’ as many religious fundamentalists claim. Stanford neuroendocrinologist Robert Sapolsky has advocated similar views, holding that the biologically ‘determined’ nature of behavior is in fact cause for compassion, rather than judgment.
Whether this kind of ‘genetic humanism’ will emerge in China remains to be seen. But Zhu is pessimistic. “I think people are afraid of being different,” he told me, “so even if people understand homosexuality is decided by genes, they will probably still oppose it.” Although overt discrimination in China against homosexuals remains rare, the prospect of a future in which those like himself are ‘weeded out’ via PGD is clearly troubling – and not only for homosexuals.
Further insights can be found in an investigation by Scientific American. Unlike in American culture where fears of “eugenics” and “an elite genetic class” still linger after experiences from the first half of the 20th century, PGD in China has little stigma attached. The practice is being widely adopted across the country, and this continues to accelerate. With yearly growth rates estimated between 60 -70%, the Chinese consumer genomics industry is already ahead of the United States and the UK, and may soon be decades more advanced if trends continue at their current pace. Although scientific limitations mean we may be years away from a tickbox for ‘sexual preference’ being offered to prospective parents, these economic indicators suggest that the Chinese cultural climate could be supportive of this kind of genetic modification, if brought to market.
Bioethicists like Dr. Jonathan Anomaly, faculty fellow at the Institute for Practical Ethics at University of California, San Diego, have been preparing for the inevitable ethical and religious firestorm such genetics advances would inevitably bring. Yet unlike some, he’s not particularly worried. According to Anomaly:
Bioethicists don’t talk a lot about selecting for sexual orientation, partly because the science has been inconclusive until very recently, and also because most bioethicists think it would be just fine to influence sexual orientation.
Most of us don’t think of homosexuality as either a disease or as immoral. The only reservation most bioethicists might have about selecting an embryo with SNPs that make a child more likely to be gay is if the child were forced to grow up in a repressive society like Saudi Arabia. But even then, we could easily imagine that instead of preventing homosexuality our moral obligation is instead to promote norms of toleration and laws that protect sexual minorities.
Such tolerance would be deeply welcomed in the mostly silent minority of gays in China, where open expressions of the kind found at gay pride parades in the west are virtually nonexistent. If a consensus develops that there is no intrinsic reason why a prospective parent should select for heterosexuality over homosexuality in their child, then the future of the LGBT community and culture in China would seem somewhat more secure. Furthermore, the repeal of the One Child Policy adds additional flexibility to prospective parents in family planning, and could alleviate fears that a homosexual child means the end of the family line.
But is this tolerance towards homosexuality found among bioethicists and the general public in Europe and North America really relevant when considering the impact of gene-editing technologies in a country so culturally distinct?
“I don’t know about the median view in Chinese bioethics.” Anomaly said. “It’s hard to know what most Chinese bioethicists believe. I suppose we might worry that the government might try to influence their views in order to promote a ‘traditional’ family free of homosexuality, but I really don’t know.”
Anomaly’s uncertainty speaks to the asymmetry of opinion on ethics and genetics that divides the East from the West. In the United States, the political and party divisions that separate the conservative-religious right from the social-justice left do not prevent them from agreeing on the issue of gene-editing technologies, albeit for very different reasons. Typically, conservatives are afraid of playing God, while liberals are more focused on worsening inequality or harming vulnerable minority groups. In China, where public opinion on bioethics issues is much harder to gauge, present indicators seem to show an unrestrictive attitude toward genetic enhancement in the broadest sense. In any case, the views of Chinese bioethicists may turn out to be irrelevant, as it is the government who ultimately acts as the final player in any regulatory decisions made.
Furthermore, while regulations on genome screening and editing in China are relatively permissive, the country is by no means a ‘wild west’ of genotypic customization. For instance, selecting for sex of the child during embryo selection is illegal in China, making it impossible to extend the infamous practice of ‘son preference’ via genetic technologies. Currently, clinics licensed to perform PGD are not allowed to select for characteristics such as height and intelligence, and are restricted to targeting health problems like genetic diseases or fertility conditions. This leaves no room for selecting against homosexuality under the current regulatory framework, although it is not directly addressed in law.
However, the reorganization of the Ministry of Health into the National Health and Family Planning Commission in 2013 may signify a change of attitudes that could one day result in an expansion in licensing permissions for clinics to accommodate parental preferences for their child’s sexuality. Indeed, the Commission’s official website states that China “advocates eugenics,” and while homosexuality is not referred to by name, its affirmation that “[r]oughly 80 percent of those with risky behaviors leading to AIDS have received intervention” leaves little room for doubt.
Ultimately, gene variants associated with homosexuality are still mostly unidentified, and selecting for sexual orientation remains years away from becoming widespread irrespective of legality. Furthermore, the effect of these genes is probabilistic rather than deterministic, leaving a great deal of deciding power to the environment, parenting, and education. Still, Ganna’s study shows that the gray fog of moral uncertainty surrounding sexual orientation and gene editing could clear into an economic and legal reality in the coming years. How this might affect homosexuals in countries like China or the United States remains to be seen – but some still find cause for optimism.
“Who knows what the future will hold?” Anomaly asks. “It’s exciting.”
A version of this article previously ran on the GLP on Nov 13, 2018.
Wael Taji is a predoctoral student in behavioral economics and neuroscience at Peking University, where he’s closely watching China’s burgeoning genomics industry. Follow him on Twitter @coevolutionist