One way to test a hypothesis is to find similar test subjects. Twin studies have frequently been used to test genetic theories. The latest twin studies regarding homosexuality are giving more evidence that homosexuality is not DNA determined.
The argument is simple enough. If a person is born a certain way, who are we to judge what they are? A person born with black skin is that way because of his or her genes. We’ve been told that homosexuality is gene-directed. A person’s DNA determines sexual attraction and identity even though the sexual organs in same-sex relationships do not line up with the genetic makeup of people of the same sex.
“At best genetics is a minor factor,” says Dr. Neil Whitehead, PhD. Whitehead worked for the New Zealand government as a scientific researcher for 24 years, and then spent four years working for the United Nations and International Atomic Energy Agency. Most recently, he serves as a consultant to Japanese universities about the effects of radiation exposure. His PhD is in biochemistry and statistics.
Because identical twins are always genetically identical, homosexuality cannot be genetically dictated.
“No-one is born gay,” he notes. “The predominant things that create homosexuality in one identical twin and not in the other have to be post-birth factors.”The predominant things that create homosexuality in one identical twin and not in the other have to be post-birth factors.
Identical twins have the same genes or DNA. They are nurtured in equal prenatal conditions. If homosexuality is caused by genetics or prenatal conditions and one twin is gay, the co-twin should also be gay.
Dr. Whitehead believes same-sex attraction (SSA) is caused by “non-shared factors,” things happening to one twin but not the other, or a personal response to an event by one of the twins and not the other.
For example, one twin might have exposure to pornography or sexual abuse, but not the other. One twin may interpret and respond to their family or classroom environment differently than the other.
“These individual and idiosyncratic responses to random events and to common environmental factors predominate,” he says.The first very large, reliable study of identical twins was conducted in Australia in 1991, followed by a large U.S. study about 1997. Then Australia and the U.S. conducted more twin studies in 2000, followed by several studies in Scandinavia, according to Dr. Whitehead.
In the identical twin studies, Dr. Whitehead has been struck by how fluid and changeable sexual identity can be.
“Sexual orientation is not set in concrete,” he notes.
“Most changes in sexual orientation are towards exclusive heterosexuality.”
“The academics who work in the field are not happy with the portrayals by the media on the subject,” Dr. Whitehead notes. “But they prefer to stick with their academic research and not get involved in the activist side.”
1. Dennis Overbye, “Born to Raise Hell?,” Time (February 21, 1994), 76