Language
Country/Area
No result found
The Biological Mystery of Sexual Orientation: Are Our Sexual Predispositions Really Innate?
The biological roots of sexual orientation have always been a hot topic of research, and scientists are still exploring this issue. Although the specific cause of sexual orientation has not yet been determined, the scientific community generally believes that it is the result of a complex interaction of multiple factors such as genes, hormones and environmental influences. Among these factors, biological theories are the most widely accepted as explanations for the causes of sexual orientation.
Biological factors may include genes, early intrauterine environment (such as prenatal hormones), and brain structure.
The evolutionary explanation for heterosexuality is relatively straightforward and is thought to be a psychological adaptation that evolved for higher reproductive success. Evolutionary explanations for homosexuality rely on other evolutionary mechanisms, such as kin selection and fitness inclusion, or against polygene expression, where the sexual orientation of some homosexuals may be due to a part of the gene that promotes heterosexuality. offspring, but in homosexuals it is a by-product.
Scientific research and research cases
Fetal development and hormonal effects
The influence of hormones during fetal development is one of the most influential hypotheses in the development of sexual orientation. In the early stages of fetal development, the initial state of the brain is the "female" state. INAH3 structures develop within the left hypothalamus as a sex-preferred structure and are not yet functional. Once the SRY gene on the fetus's Y chromosome turns on, its testicles begin to develop and release testosterone, the primary androgen hormone that causes masculinizing changes in the fetus and its brain.
If INAH3 does not receive enough testosterone to overcome circulating estrogen in the 12th week after conception, it may result in underdevelopment and possible same-sex attraction.
While there may not be a statistically significant difference in the size of INAH3 between gays and straights, research shows that gay men appear to have higher neuron density, meaning their brains may be more sensitive to sexual attraction. There will be different tendencies. In addition to these biological factors, the mother's immune response during fetal development is also considered an important process affecting homosexual orientation.
Genetic influence
Many studies have shown that genes play a significant role in the formation of sexual orientation. Although socialization theory was dominant in the 20th century, experimental results show that the impact of social environment on sexual orientation is not significant, especially among men. According to twin studies, for a pair of genetically identical identical twins, the probability of having the same sexual orientation is significantly higher than that of fraternal twins, providing indirect evidence for the contribution of genes.
Bailey et al.'s 2016 meta-analysis showed that the median concordance for same-sex sexual orientation among identical twins was 24%.
In addition, genetic linkage studies have also revealed multiple genetic factors that influence sexual orientation. In particular, some studies have pointed out that the proportion of gay men in maternal families is significantly higher than that in paternal families, which provides support for the existence of "gay genes" to a certain extent. Although these studies still need more verification, their results mean that the interaction between genes and environment is not unidirectional, but complex.
Other influencing factors
In exploring the formation of sexual orientation, there are other factors such as thyroid dysfunction that may also have an impact on its development. Research suggests that maternal thyroid-related conditions may lead to gender-specific developmental biases in children. In epidemiological studies, it has been observed that among children with autism spectrum disorder, gender-nonconforming children also show certain trends in sexual orientation. These results further highlight the biological basis of sexual orientation and its possible diversity.
To sum up, the formation of sexual orientation cannot be explained by a single factor. The combination of genes, hormones and the wider environment makes each person's sexual orientation a complex and unique result. Efforts are still being made to discover and understand more of this area, but will we ever be able to uncover the biological blueprint behind sexual orientation?
