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We are being consistently told that science says “being gay” is an inborn immutable trait of an individual that is beyond their power to change. Therefore, holding people morally accountable is cruel, unreasonable, and, worst of all, out of date and unscientific.

Originally published by the National Catholic Register


Science says: No one is born gay.

Actually, it is more accurate to say, “The available science is inconsistent with the claim that people are born gay.” I made the deliberate overstatement to dramatize a point: We are being conned with ideology masquerading as science. We are being consistently told that science says “being gay” is an inborn immutable trait of an individual that is beyond their power to change. Therefore, holding people morally accountable is cruel, unreasonable, and, worst of all, out of date and unscientific. The Catholic Church must abandon her ancient teaching that homosexual acts are “intrinsically disordered” in order to keep up with the most modern findings of science. But what if “science” says no such thing?

Before addressing this, let me point out an objective historical fact: The Catholic Church’s disapproval of homosexual acts was at one time the consensus of the entire Judeo-Christian tradition. The Church’s specific language that homosexual acts are “intrinsically disordered” flows in part from her long dialogue with Greek philosophy and has a specific philosophical meaning. Homosexual acts are not “ordered” toward the proper end of sexual acts, namely reproduction. Until very recently, the widespread Judeo-Christian view agreed roughly with today’s Catechism of the Catholic Church, that homosexual acts “are contrary to the natural law. They close the sexual act to the gift of life. They do not proceed from a genuine affective and sexual complementarity. Under no circumstances can they be approved” (2357).

As a matter of fact, the available science analyzing the human genome clearly says there is no genetic basis for a homosexual identity. A large-scale study of the human genome concluded there is certainly no single genetic determinant of same-sex sexual behavior. The study concluded that “all tested genetic variants accounted for 8% to 25% of variation in same-sex sexual behavior … and do not allow meaningful prediction of an individual’s sexual behavior.” The lead author of the study told The New York Times that it is “basically impossible to predict one’s person’s sexual activity or orientation just from genetics.” Ruth Institute senior research associate Father Paul Sullins, professor emeritus of sociology at The Catholic University of America, summarized the results of this very technical paper as follows:

“The study found that a person’s developmental environment — the influence of diet, family, friends, neighborhood, religion, and a host of other life conditions — was twice as influential as genetics on the probability of adopting same-sex behavior or orientation. The genetic influence did not come from one or two strong sources but from dozens of genetic variants that each added a small increased propensity for same-sex behavior. A genetic arrangement based on a large number of markers across the genome means that virtually all human beings have this arrangement, or large portions of it. In other words, not only did the study fail to find some controlling gene for gay identity, it also established that gay persons are not genetically distinct from all other human beings in any meaningful sense. Gay persons, we might say, have a perfectly normal human genome.”

Numerous studies of identical twins are inconsistent with the idea that being “gay” is genetically determined. If it were, we would expect 100% “concordance” between identical twins: that is, if one twin is “gay,” the other should be, as well. The actual concordance is closer to 1/3, according to a study that reviewed research conducted about this issue and stated as follows:

“Despite the fact that identical twins share 100% of their genes, gay/gay twins are less common than gay/straight twin pairs. The twin data clearly show a genetic contribution to sexuality (because even a twin concordance as low as 25% is significantly greater than would be expected by chance), but not geneticdetermination (which would produce perfect concordance in identical twins.)”

That last sentence is a clue to a more modest, less ideological idea about the origins of same-sex attraction, same-sex sexual activity and self-identification as gay or lesbian. There may be a genetic contribution to these feelings and activities, but not strict genetic determinism. There is scientific evidence consistent with this claim. Numerous complex social and psychological traits are best described in this manner: genetic predisposition or contribution to the trait, but not a hard and fast determinism.

For instance, a landmark 2015 study reviewed all 2,748 major twin studies between 1958 and 2012 of 17,804 human traits, grouped into 28 general trait domains. (Not every study examined every trait.) The closest item to sexual orientation covered by this study was called “Psychological and Behavioral Disorders Associated With Sexual Development and Orientation.” The study deduced that the heritability of this set of traits to be about 32%.

To put this in perspective, this study estimated the heritability of other social and psychological traits such as “Religion and Spirituality” to be 31%, “Eating Disorders” to be around 40%, and “Mental and Behavioral Disorders Due to the Use of Alcohol” to be around 41%.

If people are not really “born that way,” what explains why some people experience persistent same-sex attraction? Scientists do not agree on this issue. There are a number of reasons people experience persistent same-sex attraction. Even the American Psychological Association admits:

“There is no consensus among scientists about the exact reasons that an individual develops a heterosexual, bisexual, gay or lesbian orientation. Although much research has examined the possible genetic, hormonal, developmental, social and cultural influences on sexual orientation, no findings have emerged that permit scientists to conclude that sexual orientation is determined by any particular factor or factors.”

As I said above, “The available science is inconsistent with the claim that people are born gay.” People who wish to persuade the Catholic Church to change her teachings on the morality of same-sex sexual behavior cannot credibly cite “science” in their defense. At this point in history, the Catholic Church is the “last man standing” by this traditional belief that is the common heritage of the entire Judeo-Christian world.

It would be a shame for the Church to throw in the towel, right at the moment when science is proving she was right all along.


Morse, Jennifer Roback: © 2023 EWTN News, Inc. Reprinted with permission from the National Catholic Register –