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Homosexuality: A Scientific and Catholic Perspective in Vietnamese Context

Homosexuality is a social phenomenon and also a moral dilemma.  In the past, there were many misconceptions and stereotypical images about homosexuals.  Then, many people regard them with doubtful eyes, especially in Vietnamese society, where there have not been many serious and in-depth studies on homosexuals.  Furthermore, the higher incidence of HIV infection among gay and bisexual men[1] seems to reinforce antipathetic or discriminatory criticisms against homosexuals.  James Harrison calls attention to what we may not know: “gay people are colleagues we respect, relatives we love. They are friends, aunts and uncles.”[2]

As Xavier Thévenot, Don Bosco priest and professor of moral theology, once commented, many Catholics today, especially young people, feel confused when encountering profound changes in social culture. They feel that the Church’s teachings seem strange to the world. At the same time, they also wonder whether new scientific discoveries in sexuality and biomedicine can help humans progress.  How to become “more human” in today’s volatile world?[3]

I. The situation of homosexuality in Vietnam 

Vietnamese law on same-sex marriage 

The 2000 Marriage and Family Law prohibits same-sex marriage.  Therefore, same-sex marriage may be subject to administrative sanctions according to Decree 87/2001/ND-CP with a fine ranging from 100,000 VND – 500,000 VND.[4]

In 2013, according to some reports, taking the average rate of homosexuals that many scientists admit is 3% of the population, the number of homosexuals and bisexual people between the ages of 15 and 59 in Vietnam is estimated at 1.65 million. According to survey results of the Institute for Social, Economic and Environmental Studies (iSEE), when discovered to be homosexual, 20% of these people lost friends, and 15% were scolded or beaten by their families. More seriously, 4.5% had been attacked for being homosexual, 1.5% said they had been expelled from school, 4.1% had been kicked out of their accommodation, and 6.5% had lost their job.[5]

The 2014 Marriage and Family Law no longer prohibits same-sex marriage. Clause 2, Article 8 of the 2014 Law only stipulates: “The State does not recognize same-sex marriage.” Decree 110/2013/ND-CP also does not regulate administrative sanctions for marriage between homosexuals.[6] Arguments for or legalization of same-sex marriage and rulings by judges will never make homosexual behavior or same-sex marriage right. Today, along with world trends, the wave of support for homosexuals and same-sex marriage is spreading in Vietnam.  This is a great challenge for Catholic pastors and educators.

The local Church’s response 

In the rather particular situation of the country, with many political and social challenges, to be honest, the local Church does not care, or cares very little, about the homosexuals’ situation.  Parish priests repeat Church teachings without having the means to accompany people with homosexual tendencies, same-sex couples, and families with homosexual children.

In recent years, a few diocesan Bishops have been concerned about homosexuals.  Four years ago, I was invited to help with annual training for priests in a diocese as an ethics expert and doctor to address the topic of homosexuality and clerical sexual abuse.  In 2023, I was invited to help with annual training for priests in two dioceses on the subject of homosexuality.  Almost in the local Church, there are no official pastoral activities for homosexuals.  On the one hand, Vietnamese priests are still quite embarrassed to accompany LGBTQ groups.  On the other hand, knowing that the Church does not allow homosexuality, young homosexual Catholics are unlikely to be open about their sexual orientation, or they secretly live with homosexual partners.

II. Some Medical Understanding 

Some historical features 

The scientific definition of homosexuality has gradually changed and evolved over the past two centuries.  This evolution is also closely linked to the social and political definition of homosexuality.  Theories that have developed over a long time have suggested that homosexuality is a pathology and can be cured with psychological and medical treatment.  At the end of the 20th century, there was a shift in medical and psychological views on homosexuality.  Some people in Europe began to study homosexuality scientifically.  Gradually, theories about hormonal and medical origins were proposed and accepted.[7] In 1973, the American Psychological Association voted to remove homosexuality from the list of mental disorders.[8]

Research on the causes

Neurological aspect 

Since the mid-20th century, from several studies on mice, neurologists and endocrinologists Charles Barraclough and Geoffrey Harris discovered apparent differences between male and female mouse brains. They call this phenomenon sexual dimorphism.  In 1982, Christine de Lacoste-Utamsine and Ralph Holloway confirmed sexual dimorphism in humans.  Likewise, Anthony F. Bogaert and his colleagues suggest that homosexuality is biologically closely linked to hormones, brain anatomy, and brain function.[9] The above conclusion is highly controversial. In 1991, in the article “A Difference in Hypothalamic Structure Between Heterosexual and Homosexual Men” LeVay concluded that the two nuclei INAH 2 (interstitial nuclei of the anterior hypothalamus) and INAH 3 in the Hypothalamus are large among individuals with a sexual orientation toward women (i.e., heterosexual men and homosexual women), and small among individuals with a sexual orientation toward men (i.e., heterosexual women and gay men).  Many subsequent trials showed inconsistent results.[10]


For decades, scientists have proposed the “adult hormone theory” of sexual orientation, arguing that adult gays have lower levels of testosterone or higher levels of estrogen than other heterosexual men.  And lesbians showed the same pattern: lower levels of estrogen or higher levels of testosterone than other heterosexual women.  According to Chandler Burr, although the evidence from hormonal studies has, in some cases, shown that hormones play a role in sexual orientation, it has not reached a level where a firm conclusion can be drawn.[11]

Genetic factors 

Previously, scientists agreed that there was no gene that caused homosexuality.  However, they argue that genetic factors significantly influence sexual orientation.  Bailey and Pillard once studied twin samples to find similarities in sexual orientation.  In monozygotic twins, they found a 52% similarity rate.[12] However, their study sample was only 59 people.  In 2000, Bailey and two other scientists expanded the research sample to 4,901, so the similarity rate was only 20%.  In 2002, Bearman and Brückner’s study reported an even lower rate: 7.7%.  From which, they concluded that it is not clear a genetic influence on homosexual inclination.[13]

According to The Telegraph, for the first time, a complete study of the chromosomes of more than 1,000 gay men and comparison with genetic data of 1,000 other men, a research team from North Shore University Health Research Institute (USA) discovered that gay and non-gay men have some genetic differences in the genes SLITRK5 and SLITRK6.  SLITRK6 is an important gene for brain development, with a special role in activating the hypothalamus, which is responsible for forming hormones that control gender.  However, the above results are still controversial.  Some British experts say more research is needed before it is possible to determine specifically which genes are linked to gay men because genetic differences may manifest differently, such as being more open and more sociable.  Gil McVean, professor of Statistical Genetics at Oxford University (UK), believes that many factors, including environment, life experiences, and some innate biological differences, influence sexual orientation.[14]

In the 1986 “Letter to the Bishops of Catholic Church on the Pastoral Care of Homosexual Persons,” the Congregation for the Doctrine of the Faith (CDF) further distinguished external causes of homosexual inclination: “the tendency comes from wrong education, from deficiencies in normal sexual development, from habit, from bad example, or from other similar causes, and is temporary, or at least not irreparable.”

Responding to an interview with Peter Seewald in the book “Light of the World: The Pope, The Church and the Signs of The Times”, Pope Benedict XVI said that the cause of homosexuality “remains an open problem.”[15] Pope Benedict XVI commented that the legalization of same-sex marriage in many countries is a “distortion of human conscience.” The fundamental conviction is that human beings exist as men and women, that the transmission of life is a task assigned to humanity, that it is the union of man and woman that serves this task, and that in this, beyond all differences, marriage essentially consists in the transmission of life, and that this is an original conviction that has been evident to humanity up to the present”, According to him, the issue of same-sex marriage is not one of “a little more openness and openness. Rather, the fundamental question is asked: Who is human? And with that question comes the question of whether there is a Creator.”[16] 

III. A biological and anthropological observation

In terms of moral theology, it is inappropriate to label a person as homosexual or heterosexual.  Because the basic thing is the humanity and the dignity of each person.  The Church emphasizes that each human has a basic identity: the image of God and inherits the promise of eternal life.

Some theologians argue that in itself, the desire to have sex with someone of the same sex is not wrong, because even heterosexual people sometimes desire sex with someone other than their wives or husbands; or a monk, at some moment, suddenly finds himself wishing to have sex with someone.  Indeed, sexual desire for someone other than one’s husband or wife is objectively wrong, but it is not yet a moral evil.  What makes that desire bad is when that person indulges in that desire, even if only in thought; But if the person in question fights with him/herself to overcome his/her wrong desire, not only will he/she not make a mistake, but he/she will also have the “merit” of fighting.

Asian culture and oriental medicine talk about the mutual yin and yang in the universe’s operation and within humans.  When the yin and yang harmony is lost, pathology arises. In case two men or two women have sex, conception is completely impossible. This is contrary to natural law.  Reproduction is one of the aspects of sexuality in plants, animals and humans.  Some people may argue that menopausal women also have sex, but cannot give birth, or that some couples are infertile due to congenital or acquired diseases.  That is true, but these people still act according to natural male-female reciprocity.

According to the Archbishop of Malines-Bruxelles, André-Joseph Léonard, from a philosophical point of view, homosexual tendencies and practices have an orientation that is not in harmony with the objective logic of gender.  The logic of this gender consists in “distinguishing” and, in a way, “separating” male and female and thus, both can complement each other.  Moreover, that is the meaning of the word “sex,” which most likely comes from the Latin “secare”, a verb meaning “to separate.” Gender consists of separating males and females, aiming at their union through the sexual act that simultaneously opens to procreation.  The philosophical problem posed by homosexuality is that this sexual orientation somehow erases the polarity of male and female and loses the complementarity of the two sexes.

CDF declares in the document “Considerations regarding proposals to give legal recognition to unions between homosexual persons”:

“Homosexual unions are totally lacking in the biological and anthropological elements of marriage and family which would be the basis, on the level of reason, for granting them legal recognition.  Such unions are not able to contribute in a proper way to the procreation and survival of the human race.  The possibility of using recently discovered methods of artificial reproduction, beyond involving a grave lack of respect for human dignity, does nothing to alter this inadequacy.

Homosexual unions are also totally lacking in the conjugal dimension, which represents the human and ordered form of sexuality.  Sexual relations are human when and insofar as they express and promote the mutual assistance of the sexes in marriage and are open to the transmission of new life.” (n.7)

IV. Pastoral care for homosexuals in the Vietnamese Context 

The Church sympathizes and welcomes people with homosexual tendencies and understands their challenging situations.  In Vietnam, one of the first issues of homosexuality is liberation from stereotypical thoughts, descriptions, and some forms of discrimination.  The local Church’s mission to homosexuals has always been pastoral. It does not simply repeat the challenge Christ posed to a generation; it seeks to work with each individual, taking into account each person’s strengths and weaknesses and helping the individual carry out his/her responsibilities as fully as possible in each moment of life. 

Pastors and counselors must be sensitive to the inner turmoil that can be part of the experience of homosexuals.  Homosexuals may feel that nature has deceived them and created unnecessary tension.  Their sexual orientation is not due to personal fault but instead gives rise to a wave of societal opposition and rejection.  In a number of cases, homosexuals may feel that the Church is demanding impossible standards.

However, even for heterosexual people who are single, there are times when they feel the need for physical sex, but that does not mean they can seek physical relationships outside of marriage.  Therefore, homosexuals are also invited to overcome physical sexual needs through psychological and spiritual measures such as prayer, strengthening intellectual and supernatural life, and expanding charitable activities to serve people in need such as sick and poor people.

There seems to be an indelible gap between doctrine and practice.  On the one hand, doctrines have a strict structure in which each element is classified into clear categories, the relationships between elements are precisely defined, and the types of good and evil are clearly defined.  On the other hand, reality is extremely complex and cannot be arranged into the categories clearly defined by moral textbooks.  Moralists, spiritual directors, and confessors must always use wisdom based on compassion, to discern and find appropriate solutions for each case.[17]

Thanks to the law of gradualness, moral theology recognizes that the morality of behavior is not only black or white but that there is also gray between black and white.  Certainly, gray is not white, but it is not really black either, and cannot be considered black!  However, it must be emphasized again that if it is not always required to immediately and completely apply the rule, it is always necessary to strive to find a way to fully apply that rule.  This direction must be real and vivid, meaning it has the purpose of helping us expand and realize as soon as possible the value that the law protects.

The law of gradualness can help reduce the sense of guilt in Christians who, despite their efforts, do not always come to live out all the moral requirements.  It can also help the Christian to distinguish the goal aimed at and the good that he/she sincerely achieves.  This law provides a foundation for a better pastoral understanding of difficult situations, such as homosexuals, to find more merciful pastoral solutions.  Homosexuals are called to live holiness in their very special situations by their right moral choices and decisions in good faith.

[1] Thư Anh, “Alarming HIV infection due to male homosexual sex”, < 4221054.html>,

[2] Rf. James Harrison, “The Dynamics of Sexual Anxiety”, Christianity and Crisis 37 (1977), p.136-40, cited in Vincent J. Genovesi, In Pursuit of Love, Catholic Morality and Human Sexuality, 2nd ed. (Philippines, 2003), p. 250.

[3] Rf. Xavier Thévenot, Repères étiques pour un monde nouveau, (Mulhouse, Salvator 1983), p.4-5.

[4] “Vietnamese law on same-sex marriage,” <>..

[5] Thảo Nguyên, “Vietnam has about 1.65 million homosexual and bisexual people”, <>.

[6] Kenny Nguyễn, “Homosexuals misunderstand that same- sex marriage is allowed”, <>.

[7] Vũ Văn An, “Discussing same-sex marriage: the scientific aspect”, <>.

[8] Vũ Văn An, “Discussing same-sex marriage: the scientific aspect”.

[9] Anthony F.  Bogaert, Ray Blanchard, Lesley E.  Crosthwait, “Interaction of Birth Order, Handedness, and Sexual Orientation in the Kinsey Interview Data”.  Behavioral Neuroscience  121 (2007), p. 846-853. <>.

[10] Vũ Văn An, “Discussing same-sex marriage: the scientific aspect”.

[11] Ibid.

[12] Dr. Paul Wertsch, “The Medical Community’s Understanding of Homosexuality,” <>.

[13] Vũ Văn An, “Discussing same-sex marriage: the scientific aspect”.

[14] Trọng Nhân, “Detecting genes related to homosexuality”,  <>.

[15] Benedict XVI, Light of the World: A Conversation with Peter Seewald (San Francisco: Ignatius Press, 2010), p, 152.

[16] Đặng Tự Do, “Pope Benedict: Legalizing same-sex marriage is a distortion of humanity”, <>.

[17] Alain You, “La loi de gradualité… et non pas la gradualité de la loi”, in Esprit et Vie, (28.2.1991), p. 120-127.