According to a large study, genetic markers linked to same-sex encounters may enhance reproduction. However, some scientists doubt the findings.
According to evolutionary biologists, there is a contradiction in the genetics of homosexuality. When it comes to homosexuality in humans and other animals, it is theoretically impossible for them to have many biological children. Any genes that incline people to homosexuality are unlikely to pass on to their descendants. Despite this, research reveals that the attraction between people of the same sex is a result of genetics.
To date, researchers have analyzed the genetic data of hundreds of thousands of people and discovered patterns that may be linked to homosexuality and the ability to find and have children with partners of another gender.
University of Queensland evolutionary geneticist Brendan Zietsch and his colleagues used data from the UK Biobank (UK), the US National Longitudinal Study of Adolescent to Adult Health (US), and the company 23andMe (California), all of which collect information from their participants by analyzing their genetic data and conducting questionnaires. Four hundred seventy-seven thousand five hundred twenty-two persons who indicated they’d had at least one sexual encounter with someone of their gender were compared to 358,426 people who said they had only experienced heterosexual relations to see if there was any genetic variation. Only participants of the same gender and sex were included in the study, which only looked at biological sex, not gender.
According to previous studies, people who’d had at least one same-sex partner shared patterns of tiny genetic changes spread throughout the genome. Previous studies have shown no evidence of a ‘gay gene’ based on these findings, which are consistent with the results of this study. The collection of variations explained only between 8% and 25% of heritability, but this had a negligible influence overall.
The researchers then utilized a computer technique to mimic human evolution over 60 generations. They found that unless it helped humans live or reproduce, the wide range of genetic differences associated with same-sex behavior would have eventually gone.
Gene duplication is a common occurrence.
To see if these genetic patterns could give a person an evolutionary advantage by increasing the number of sexual partners, Zietsch and his team decided to experiment. They categorized the participants who had only had heterosexual sex by the number of partners they claimed to have had and discovered that those with many partners had some of the team’s characteristics in persons who had a same-sex partner.
According to the study’s findings, people who’d had same-sex interactions were found to have genetic markers with those who characterized themselves as adventurous and open to new experiences. People with genes linked to same-sex behavior and those considered attractive by interviewers were heterosexual. When it comes to the study’s findings on sexual orientation, Zietsch adds, “We’re just guessing” because attributes such as charisma and sex desire were not included in the data.
The researchers themselves have pointed out a number of the study’s flaws. All participants were of European ancestry and lived in the United Kingdom or the United States. There were also questions concerning sexual behavior in the databases’ questionnaires. Homosexuality was either illegal or culturally taboo in many countries when the participants were born. Thus, many people attracted to persons of the same sex may never have taken action and thus ended up in the wrong group in the study.
According to Yale University ecologist and evolutionary biologist Julia Monk, the paper’s restrictions are so significant that no definite conclusions concerning genetics and sexual orientation can be drawn. It’s difficult to deduce the relevance of sexual behavior and reproduction in human evolution since they have a different place in modern society than they had for our predecessors, she says. Now that sexually transmitted illnesses may be cured, people may choose to have more sexual partners. Genetic advantages in reproduction are greatly diminished by the availability of birth control and fertility therapies. According to the study’s lead author, Dr. David Monk, there is no way to fully understand human sexual and reproductive behavior without delving into the cultural influences that shape it.
Weakness in the chain
Though the study was well-conducted, psychologist Qazi Rahman of King’s College London is skeptical of some findings. When people are eager to expose their sexual behavior to researchers, it could be viewed as a risky action that could show up in genetic data, according to him. When the data are divided between men and women and those who had only interacted with people of the same sex, and those who had interacted with persons of the opposite sex, there are so few people in each category that the genetic ties between them become weak.