Ongoing political controversies around the world exemplify a long-standing and widespread
preoccupation with the acceptability of homosexuality. Nonheterosexual people have seen …

The present review focuses on the brain structure of male-to-female (MtF) and female-to-
male (FtM) homosexual transsexuals before and after cross-sex hormone treatment as …

What causes a child to grow up gay or straight? Neuroscientist Simon LeVay summarizes a
wealth of scientific evidence that points to one inescapable conclusion: Sexual orientation …

Although sexual behavior is controlled by hormonal and neurochemical actions in the brain,
sexual experience induces a degree of plasticity that allows animals to form instrumental …

Sexual orientation is a core aspect of human experience and understanding its development
is fundamental to psychology as a scientific discipline. Biological perspectives have played …

The fraternal birth order effect is the tendency for older brothers to increase the odds of
homosexuality in later-born males. This study compared the strength of the effect in subjects …

To better understand sexual orientation from an evolutionary perspective, we investigated
whether, compared to heterosexual men, the fewer direct descendants of homosexual men …

Despite historical increases in the number of individuals engaging in same-sex relations
and entering same-sex unions, the causes of sexual orientation remain an open question …

There is a long-standing debate on the role of genetic factors influencing homosexuality
because the presence of these factors contradicts the Darwinian prediction according to …

In Western cultures, male androphiles tend to have greater numbers of older brothers than
male gynephiles (ie, the fraternal birth order effect). In the non-Western nation of …