Studies into the causes of sexual orientation have concentrated on
male homosexuality. Six studies are described in greater detail in
another essay on this web site. More studies
are described in an additional essay. All of
the studies show that genes play a significant role in determining
homosexual orientation. None of the studies show that the environment is
solely responsible. We did not pick and choose the studies which are
reported here. We have reported all that we have found, regardless of
outcome.
Studies on monozygotic twins: These are twins that resulted
from the splitting of a single fertilized egg -- the zygote -- into two
separate zygotes with identical genetic structure. They are commonly
called "identical twins." Studies have been made which
involve identical twins who were separated at birth and have not been in
contact since. Studies consistently show that male homosexual
orientation is mainly (perhaps entirely) determined at conception by a
person's genes. This is such an important and definitive study
that we
describe it in more detail in another essay.
Suicide implications: The National Institute of Health (a US Federal Government agency) reported that as
many as
30% of youth suicides are by gays and lesbians. That is, homosexual young
people commit suicide at a rate as high as six times the normal value. These are
committed by youth who are certain that they are stuck being gay or lesbian for the rest of their
lives. These young
people who commit suicide may have been taught by their
families, religious institutions, schools etc to hate or reject
homosexuality. If they had any hope of changing their
orientation, they probably would seek counseling instead of killing themselves. Most
probably believe that their sexual orientation was genetically caused
and is unchangeable.
Introspection: Most sexually active adults are aware that their sexual orientation is not chosen and
not changeable. Assuming that you are a heterosexual:
Consider how you would change yourself so that you were sexually attracted to a person
of the same gender. You will realize that it is quite impossible to create feelings of
sexual attraction if they do not currently exist.
Consider at what age you chose your sexual orientation? You will realize that, as far
back as you can remember, you were either asexual or heterosexual.
Sponsored link:
Irrationality of choice: In the forward to the book "We Were Baptized Too: Claiming God's Grace for
Lesbians and Gays", Anglican Archbishop Desmond Tutu of South Africa writes
"Someone has said that if this sexual orientation were indeed a matter of personal
choice, the homosexual persons must be the craziest coots around to choose a way of life
that exposes them to so much hostility, discrimination, loss, and suffering."
Brain Structure: Simon LeVay, a Neuroanatomist at the Salk Institute in California published a study
in 1991 which examined the brains of men who had died of AIDS. He found that the INAH 3 (a
structure within the hypothalamus) differed in size between heterosexual and homosexual
men. This suggested to the researcher that "sexual orientation has a biological
substrate". 2 This study has been criticized on a number of grounds. Many of his
subjects died of AIDS; perhaps the difference in structure size was caused by the disease,
or the medications that they took, not the sexual orientation. Others have
suggested that homosexual or heterosexual activity may have determined
the size of the structure, rather than vice-versa.
Hearing: A group of researchers at the University of Texas found
structural differences in the inner ears between
lesbians and heterosexual women. On average, women have more sensitive cochlea amplifiers
than men; they are able to detect softer sounds in a very quiet room. The researchers found
that lesbians had inner ear characteristics that were more like those of men. The
structure of the inner ear forms before birth and is affected during pregnancy by
androgens. 7 These findings indicate
that sexual orientation is at least partly decided before birth -- perhaps at conception.
Incidence: Gays and lesbians do not appear to be any less common in societies which condemn and
suppress homosexuals; they do not seem to be any more common in accepting societies.
This would argue against sexual orientation being learned from the
environment.
Parenting: Almost all children raised in families headed by two gays or two lesbians grow up
heterosexual. The sexual orientation of one's parents appear to have little or no
influence over the orientation of their children.
J.M. Bailey, R. C. Pillard, "A Genetic Study of Male Sexual Orientation",
Archives of General Psychiatry, 48 (1991): 1089-96.
J. M. Bailey, R. C. Pillard, et al, "Heritable Factors Influence Sexual
Orientation in Women" Archives of General Psychiatry, 50 (1993): 217-23.
Chandler Burr, "A Separate Creation: The search for the biological origins of
sexual orientation", Hyperon, New York, NY (1996)
J.A.Y. Hall & D. Kimura, "Dermatoglyphic Asymmetry and Sexual Orientation in
Men", Behavioral Neuroscience, Vol. 108 #6, 1994-DEC, P. 1203-1206.
"Lesbian Ears", The Globe and Mail, Toronto ON, 1998-MAR-19.
Jeff Donn, "Finger length linked to sexual orientation: Male
hormones in womb produce differences: study," Associated Press,
2000-MAR-29
Article, title unknown, Nature, 2000-MAR-30.
Robert T. Lee, "Against Homosexuality," The Society for the
Practical Establishment and Perpetuation of the Ten Commandments,"
1998-JUN-20, at:
http://www.tencommandments.org/homosexual.html
Matt Ridley, "Nature via nurture: Genes, experience, and what makes us
human," HarperCollins, (2003). Read
reviews or order this book safely from Amazon.com online book store
This book discusses the effects of genes and the environment on human behavior
and traits. It touches on homosexuality in a few locations.