Nowhere is the gulf between science and religion more evident and more enormous than when we confront the issues of sexuality, sexual orientation, gender identity, and homosexuality. It seems bizarre that in the 21st century so many people in America and elsewhere are still confused by ignorance and self-deception--by rampant stupidity.
The science of the issue is clear to every biologist and was cogently summarized in a recent review by two endocrinologists (1). The authors make the following points:
The above points are made by endocrinologists, but you don't need to be an endocrinologist to understand the facts and the implications.
The first important implication is that sexuality and sexual orientation and gender identity are not questions of choice but matters of biology and hormones and circumstances in the fetal environment.
The second important implication is that all the chief religions are apparently completely out of kilter in their understanding of biological realities concerning these issues.
The third important implication is that there's no rational basis for prejudice, discrimination, or persecution of homosexuals, transsexuals, or whatever--and in fact such hostile attitudes are from the standpoint of science and reality blatantly disgusting.
Most religions base their doctrines on ancient books with obsolete knowledge of the real world. As the human species moves forward in time, our knowledge of the real world increases in quantity and quality, and it seems to me that any religion that hopes to survive must either change its books or ultimately implode for lack of relevance.
Meanwhile, people in and out of religion need to understand the reality of the 21st century. We need to understand that the human species exhibits a whole spectrum of sexualities, sexual orientations, and gender identities, a smooth continuum from extreme female to extreme male, with all sorts of combinations of orientation and identity and sexuality in between the extremes.(2) That's biological reality--and for the sake of sanity it should be our social reality. There's no reason to oppose gay marriage except stupid ideas based on old books, irrational fears, and psychiatric hatreds. It's time to grow up.
Note (1). Garcia-Falgueras A, Swaab DF. (2010). Endocr. Dev. 17:22-35.
Note (2). A full discussion of fetal variables in sexuality and gender identity plus some interesting cases can be found in Chapter 7 of my new book More Than Genes, Oxford University Press, 2009.