Sexual orientation is a complex and sensitive topic, and different people may have different preferences and tendencies. However, the genetic and evolutionary basis of sexual orientation has been a difficult problem for scientists to explore. Why do some people become interested in same-sex or bisexuality? Is this sexual orientation conducive to survival and reproduction? Are there specific genes that determine our sexual orientation?
A recent study published in the journal Science Advances provides some clues to these questions. The study found that there are some genetic variants that are associated with both bisexual tendencies and risk appetite in men. These genetic variants may help bisexual males survive natural selection because they are more willing to take risks, increasing their chances of mating and the number of offspring.
The lead authors of the study are Professor Jianzhi Zhang and Dr. Siliang Song from the University of Michigan. They used data from the UK Biobank, a vast database of 450,000 genetic samples and detailed behavioural surveys. They first screened for genetic variants associated with same-sex or bisexual behavior, and then analyzed the association of these genetic variants with other traits.
They found that the genetic variants associated with same-sex or bisexual behavior were not a uniform group, but could be divided into two categories: one that was only associated with pure same-sex behavior, and another that was associated with both bisexual behavior and risk preference. The risk appetite of the latter includes gambling, smoking, drinking, drugs, etc.
They further found that genetic variants associated with intersex behavior and risk preference were also associated with the number of offspring in males. That is, males who carry these genetic variants may not only be bisexually interested, but may also be more adventurous, increasing their chances of mating with the opposite sex and the number of children. In this way, these genetic variants can be preserved in natural selection without being eliminated.
This discovery provides a possible mechanism for solving the evolutionary mystery of sexual orientation. Because, from an evolutionary point of view, if a trait causes a person to be less ferdile, then that trait is eliminated by natural selection. Same-sex or bisexual behavior, on the other hand, obviously reduces the fecundity of an individual, as they reduce the chances of mating with the opposite sex. So why do genes for same-sex or bisexual behavior still exist?
The research of Professor Zhang Jianzhi and Dr. Song Siliang provides a reasonable explanation: the genetic variants associated with bisexual behavior may also lead to another trait conducive to reproduction, that is, risk preference. Risk appetite can make individuals more courageous and charismatic, thereby attracting more opposite-sex couples and increasing the number of offspring. In this way, genetic variations in intersex behavior can survive natural selection through the mediating effect of risk preference.
Of course, this study is not to say that all bisexual men are risk enthusiasts, or that all risk enthusiasts are bisexual. These genetic variants are only one factor, not the only determinant, of sexual orientation and risk appetite. Sexual orientation and risk appetite are also influenced by the environment, education, culture, and other aspects. Moreover, this study is only based on data from the United Kingdom, and whether it applies to other populations remains to be further verified.
There are still many unsolved mysteries about the evolution of sexual orientation. For example, why genetic variations in homosexuality have not been eliminated, why same-sex or bisexuality is also prevalent in the animal kingdom, and why is there a continuous or discrete distribution of sexual orientation? These questions require more scientific research and exploration to unravel their mysteries. However, in any case, we should respect and tolerate everyone's sexual orientation and choices, because it is a fundamental right and freedom for everyone.