Sexual Orientation is in the Brain
Several other studies indicate that sexual orientation — heterosexuality,
bisexuality, and homosexuality — is determined by peculiarities of the brain structure and differences in brain chemistry. Cultural or societal factors, upbringing, moral leanings, and educational attainments do not determine sexual orientation as greatly as neural mechanisms do. In fact, scientists have identified several areas of the brain that they believe determine sexuality in an individual. These areas include the hypothalamus and the amygdala. Inter-hemispheric neural connectivity has also been found to contribute significantly to sexual orientation.
A landmark study by Savic and Lindström indicates that there are cerebral differences in homosexual and heterosexual individuals. There are differences in brain anatomy, activities, and neurological connections. Brain scan images of the subjects who participated in this study show that the brains of homosexual individuals exhibit similar structure and functionality as that of heterosexual individuals of the opposite gender.
According to the study, lesbians and straight men have similar brain structures and functionalities while gay men and straight women share neural characteristics. For instance, MRI findings prove that the right hemispheres of the brains of the lesbians and heterosexual men have slightly greater volumes than their left hemispheres. But the left and right hemispheres of gay men and heterosexual women are symmetrical.