The Biology and Spirituality of Human Sexuality
Class 6: Current Scientific and
Medical Understandings of the Biology of Sexuality
July 13, 2003
(Revised 15 July 2003)

Introduction

     Review of Last Class. In last week's class, we discussed the homoerotic practices of ancient Greece and Rome and how the Jews and early Christians viewed them.

Homoeroticism. In ancient Greece homoerotic practices were an everyday part of the community and the culture. The principal homoerotic relationship was between adult men and younger men. These pederastic relationships were an essential part of the training of young men to become full adult members of the community. The Greeks believed that men could not have a deep, all-encompassing relationship with a woman. it was the goal of pederastic relationships to achieve this. The relationships between partners were not equal. Sexual satisfaction was the privilege of the active partner only. The passive partner was to "give" to the active partner, and not even aspire to sexual satisfaction; this is in keeping with the Platonic notion of controlling the passions. Pederasty was a matter of initiation. Importantly, the initiation was not really sexually motivated, but rather spiritually and culturally inspired. Pederastic relationships were formative, designed to raise youths who would defend their community in a manly way. These relationships were not to replace heterosexual relationships. Boys were expected to mature, take wives, and becomes teachers of other young men. Husband-wife sexual relationships were for the purpose of procreation and for satisfaction of the male sexual appetite. Marriage did not end pederastic relationships; adult men often retained their boy lovers after marriage.

     In ancient Rome, pederasty was not viewed as foundational or pedagogical, and did not hold any moral value as the practice held in ancient Greece. The sexual dimension of male-male relationships was emphasized in Roman culture. Pederastic relationships between freemen were uncommon, and may have been illegal; pederastic relationships normally occurred between master and slave. Male homosexual prostitution was common, legal, and tolerated in Rome (the prostitutes were often foreigners or slaves). Such prostitutes had no social respect. A major difference between Greece and Rome was that in Rome, pederastic relationships were to stop after marriage to a woman.

     Female homoerotic relationships did not get as much press as male-male relationships. But, based on the information we do have, there was no social hierarchy with respective active-passive roles. The female homoerotic world was more egalitarian in which emotional intensity rather than sexual passion is privileged. Because male-dominated Greek culture was unable to comprehend the kind of social polity and personal interaction among lesbians, it dismissed lesbian homoerotic activity as "uninteresting."

     The early Jewish view of pederastic relationships was that they represented idolatry. Idolatry was at the root of evil, and idolatry was the blight that laid at the root of immorality. A Jewish perspective on homoeroticism was that it was unnatural - it changed the ordinary way things are supposed to be, into something "un-ordinary," and this caused a change in the divinely ordered way things were supposed to be. In this vein we discussed the stories of Lot and the Nephilim from Genesis. Later Jewish perspectives saw homosexual behavior was a Gentile vice. Homoerotic behavior was a severe form of covetousness, and all homoerotic relations were condemned because they converted men to women, and distorted the main purpose of sex which was procreation.

Pre-Modern Church Views of Homosexuality and the Development of Same-Sex Marriage Rites. The next topic we covered was how the early Christians viewed homoerotic relationships. We learned that the very early church did not distinguish between same-sex and opposite-sex unions. Several rites for the marriage of same-sex couples were developed by the early church. However, during the medieval period, the Church became increasingly ascetic. Eventually a code was adopted (the Theodosian Code) that contained a penalty against same-sex unions. It is believed that the adoption of this policy is related to the increasing ascetic influence throughout the church as opposed to Christians trying to ban a specific homosexual practice seen as immoral. The code also included a mechanism for dissolution of same-sex unions. However, despite the adoption of the Code, it was apparently not enforced, because existing 9th century same-sex ceremonies have survived, and they are very parallel to 9th century heterosexual marriages. Also, 11th century Byzantine law makes shows that legal same-sex unions were relatively common, although sometimes technically disputed in some ways.

     As we discussed in Class 4, by this time in Church history, considerable attention was being paid to the morality of the clergy - especially during the monastic period. Consequently, monks were prohibited from heterosexual and homosexual relationships in both the western and eastern churches. A good deal of the concern about unions was not just moral, it was also about inheritance of position within the monastic orders. By the 14th C, western Europe was gripped by a rabid and obsessive preoccupation with homosexuality.

     Today's class. It should be clear by what we have discussed so far is that the pre-modern view of sexuality is that one's sexual identity and practices are personal choices. The Jewish perspective, the early church perspective, and the Biblical perspectives all suggest that there is an inherent "ordering" of sexuality (i.e., that there is a male specie, who is to actively penetrate the partner, and a female specie, who is to passively receive the male). Based on this perspective, the pre-modern concept is that men were to be men and women were to be women, and any deviation from this scheme was a matter of human willfulness to go against nature. In today's class we will look at this notion from a scientific point of view to ask the question of whether this dualistic view of nature is supported by our current scientific understanding. Note that scientific understanding is an ever changing landscape, and what is written here is likely to change as new information is obtained.

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History and Background

     Up to now, we have been looking at the twin subjects of sexuality and homosexuality from biblical, traditional, and cultural perspectives, and in Class 4, we defined homosexuality as a sexual orientation that takes form in human behavior. For example, we decided that a man is a homosexual if (1) he feels sexual attraction toward other males; (2) acts upon that feeling; and (3) forms a loving bond with another male.

     As noted above, without specifically saying so, we have been working under the assumption that being a homosexual is a matter of personal choice. This assumption is completely in keeping with kind of material we have worked with so far. The Biblical record points to the theological belief that God imparted into nature specific natural laws. Sexual expression is procreative is one of the natural laws reflected in the Bible and in traditional interpretations of scripture. Another natural law that one can assume from the Biblical record is that there is a division between males and females. The Greeks carried this to an extreme (my opinion) in setting the genders in opposition with each other based on views of the importance of the passions and reason (see Class 5). A third natural law that is assumed by the Biblical record and its interpretation by the Church is that that the logical, reasoning male is the active partner in sexual activity, and that his natural counterpart is a receptive, passive (and passionate) female. As we saw in Class 4 and Class 5, deviations from this natural order were considered impure or profane (that is, not sacred). Working in this framework then, homosexuality is a considerably profane activity, because it violates each of these Biblically inspired, culturally and traditionally interpreted "natural laws."

     But what would happen to these assumptions if it was determined that homosexuality was in fact not a choice? Would that not open the possibility that the rare (2-10% of the general population is homosexual - see Class 7 for a discussion of the incidence of homosexuality), but identifiable characteristics associated with homosexual expression is part of creation? Chandler Burr writes that "homosexuals have long maintained that sexual orientation, far from being a personal choice or lifestyle, is something neither chosen nor changeable; heterosexuals who have made their peace with homosexuals have often done so by accepting that premise. The very term 'sexual orientation,' which in the 1980s replaced 'sexual preference' asserts the deeply rooted nature of sexual desire and love. It implies biology."[1] There are three interrelated areas that we will discuss: neuroanatomy, neuroendochrinology, and genetics. We'll define these as we get to them.

     Homosexuals once classified as diseased human beings. (Slide 2; ) Thus far in our studies, we have seen that people who engaged in homoerotic acts from Biblical times through the pre-modern period (ca. 16th C), were willful sinners, guilty of violating natural law, but they were not characterized as a different class of being. Even after the church defined homosexual activity as a sin and a punishable crime, those who committed the crime were not categorized differently than people who committed other kinds of crimes like murder, adultery, etc. However, during and after the enlightenment, homosexuality began to be seen as a pathological form of mental illness. By the 1940s, homosexuality was included in discussions of psychopathic, schizoid, and paranoid personality disorders. (Slide 3; )

     When homosexuality was defined as a disease, the medical and psychiatric establishments began to treat it as a reversible condition. Various treatments were tried including castration for gay men, hysterectomy for lesbian women, electroshock therapy, and transorbital lobotomy (using a metal probe inserted through the eye socket to scramble the front part of the brain). Evelyn Hooker, a psychologist, worked for nearly 20 years with homosexuals and provided the first, solid, objective evidence that defining homosexuality (Slides 4 and 5; ) as a "disease" was in fact impossible. In 1973, the American Psychiatric Association removed homosexuality from the official Diagnostic and Statistical Manual.[2](Slide 6; )

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The Normal Sequence of Events for the Development of the Sexes

     Beginning shortly after birth, the human embryo will undergo a series of developmental steps that will give rise to the gonads and genitalia. Nova has developed an animated cartoon that you can view. Click here to see this short cartoon.

     This short cartoon illustrates the fundamental idea that as a species, we are dimorphic with regard to gender: about half of us are females, and about half of us are males. Or are we? What is the biological basis for sexual dimorphism?

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Neuroendrinocrinological Evidence for Sexual Dimorphism

     In the late 1950s and early 1960s there was a burst of activity regarding the role of hormones in sexuality (remember that the birth control pill was developed at about this time). One discovery was that the male hormone, testosterone was responsible for "masculinization" of developing rats. Three observations were made in this area. (Slide 8; ) First, if female rats are injected with high doses of testosterone, they will not ovulate. Second, if male rats are castrated, and then injected with estrogen, one of the female hormones, they will produce all of the brain chemicals normally produced during ovulation. Third, and most importantly, if male rats are deprived of testosterone during the first five days of life, their brains will continue to behave as female brains; that is, they will produce the hormones characteristic of a normal female brain. (Slide 9; )

     The conclusion of this work is that there is a specific time period during which male hormones must be experienced by a developing embryo (or neonatal animal) in order for the brain to become "masculinized." If that does not occur, the brain of the embryo will be forever set as female. Thus the "default" setting for all animals is female. Sexual differentiation of the brain is dependent on production of specific hormones at specific times during gestation. (Slide 10; )

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Neuroanatomical Differences Between Female and Male Brains

    Although the studies are far and few between, some major contributions toward our understanding of sexual dimorphism have been made in studies of rats and human beings. In the early 1970s, two researchers noted that female rats had more connections between nerve cells in the hypothalamus of the brain. The hypothalamus is a small structure located at the base of the brain that controls the autonomic (reflex) nervous system which subconsciously controls the body's internal activities. It is also a major part of that part of the brain called the limbic system, which is responsible for the fight or flight response. One part of the hypothalamus is involved in the affective nature of sensory input - including the reception of pleasurable or painful stimulation. In the late 1970s, another group of researchers found that a small collection of nerve cells (called a 'nucleus') was five times larger in male rats than female rats. (Slide 11; ) These two studies demonstrated sexual dimorphism in rat brains, which was a major finding, because up to that time, it was assumed that the anatomy of male and female brains was identical. But what about human brains?

     The first and highly controversial study to purportedly show differences between the brains of the human sexes was reported in the early 1980s. (Slide 12; ) A portion of the brain called the corpus callosum (a large bundle that connects the left and the right hemispheres together) was different between men and women. In particular one part of the corpus callosum called the splenium was larger in females than males. This study has not been replicated by other scientists, so we must take take a measured view of this finding.

     In the early 1990s papers began to appear in the literature that suggested differences between the brains of human beings. One paper published in 1990 showed that a structure called the suprachiasmic nucleus, a brain region responsible for the daily rhythm of the body's functions, was larger in homosexual men than in heterosexual men.[3] A second paper published a year later showed that a small region in the hypothalamus of men was larger than it was in women. (Slide 13; ) Finally, another paper looking at this same region of the brain found that it was smaller in homosexual men and in women, suggesting that this nucleus was not just dimorphic with regard to gender, but also with regard to sexual orientation - at least in men.[4] The brains of lesbian women were not studied in this last paper.

     A paper published in 2001 used magnetic resonance imaging (MRI) to evaluate normal sexual dimorphisms of brain regions, by surveying 48 normal adults. (Slide 14; ) Sexual dimorphisms of adult brain volumes were more evident in the cortex, with women having larger volumes, relative to cerebrum size, particularly in frontal and medial paralimbic cortices. Men had larger volumes, relative to cerebrum size, in frontomedial cortex, the amygdala and hypothalamus. It is importance to note that the areas of difference corresponded to those areas that have been shown in animal studies to have greater levels of sex steroid receptors during critical periods of brain development.[5]

     These results are intriguing, but like all scientific data, they need to be interpreted with caution. The human studies have not been repeated, so their conclusions must be viewed tentatively. One of the difficulties in studies of human beings (as opposed to laboratory animals) is that human beings are not genetically identical, and large numbers of matched anatomical specimens are often times not available. Also the ways in which studies are compared to each other vary. Consequently, the data must be viewed cautiously. Finally, the relationship between cause and effect must be kept in the back of the mind. Just because differences are found, the question must be answered as to whether those differences are involved in determination of sexual orientation.

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Genetic Studies

     The above studies raise the possibility that anatomical, endocrinological, or biochemical differences may contribute to sexual orientation. If true, how do such differences arise? Are they random, but relatively rare, or are they possibly genetically determined? The latter question is not possible to answer, because we do not really know that much about what specific human genes do. But it is possible to determine whether there is some genetic predisposition for a particular trait. A particularly useful population to study genetically are twins.

     There are basically two kinds of twins: fraternal or dizygotic and maternal, or monozygotic. Dizygotic twins arise from two separate eggs that are fertilized at the same time. Although such twins develop in the same womb together, they are genetically different individuals - no more similar than any other brother-brother or sister-brother pair. Fraternal twins have about a 50% match in their DNA. Monozygotic twins, on the other hand, come from the same fertilized egg that divides in a unique way just after fertilization. These twins are genetically identical. All twins share a common environment while in the womb. If one is interested in searching for inheritable differences, identical twins provide the source material. Comparison of a characteristic in twins with the same characteristic in the siblings filters out environmental influences.

     In the early 1990s, Bailey and Dillard interviewed homosexual and heterosexual brothers who responded to advertisements they placed in gay newspapers and periodicals (note this study was conducted in men).[6] One hundred and ten pairs of male twins were interviewed, half identical, half fraternal. (Slide 15; ) One twin was was known to be homosexual, and the researchers contacted the other twin to determine his sexual orientation. Among the identical twins, 52 percent of the brothers were homosexual. Among the fraternal twins, the number was 22 percent. These numbers were significantly enough above the background incidence of homosexuality in the general population rate to suggest that there is something inheritable involved.

      Seeking confirmation of these results, Bailey analyzed the Australian Twin registry in which 5,000 twins are registered. Bailey saw the same pattern there too, but the numbers were much different. In that study, only 20% of the identical twins were homosexual. Finally, Bailey analyzed the prevalence of lesbians in twins and sisters and found a 48% concordance rate for homosexual preference in female monozygotic twins, a 14% rate among fraternal female twins, and a 6% rate between adoptive sisters.[7] (Slide 16; ). Yet again, when Bailey repeated this study using the Australian twin registry, the incidence of lesbianiasm was about half of what he saw previously (24% for identical twins and 10% for fraternal twins). These discrepancies can largely be attributed to sample bias in the original studies (probably due to his sampling methods in the original studies).

     Nonetheless, because the incidence of homosexual orientation is higher than the average for the general population (about 2-10%), these studies do suggest that there is something genetic that can predispose some people to homosexual behavior. However, it is important to not make a mental association between a genetic predisposition with the anatomical or biochemical information provided earlier. The two findings may or may not be related. We simply do not know. (Slide 17; )

     An Important Caveat. How scientific data are used and reported is a significant problem for both sides of the debate about homosexuality in the church. If you are interested in reading a thoughtful approach to this issue, I recommend the book by Stanton L. Jones and Mark A. Yarhouse in the bibliography. In that book, Jones and Yarhouse look carefully at the data and present views about how the data have beenm used in the debates in the Episcopal, Presbyterian, and Methodist churches.

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The Five Sexes

     Up to now, we have been seeking a biological explanation for homosexual orientation. However there is another group of people who are biologically outside the boundaries of maleness or femaleness, and who may have sexual orientations that do not match their physical appearance. This is a special group of people - often overlooked - but a group in which all of the issues of human sexuality are brought together.

     As we discussed in the first class, there are thirteen factors that contribute to human sexuality. (Slide 18; ) Two of those were the chromosomes and the gonads/external genitalia. Chromosomally, there are two sex chromosomes, the X and the Y. Only males have the Y chromosome. Males are XY and Females are XX. However, there are people born with XXX, single X, XXY, and XYY. "Y-ness" equates with male characteristics. It is estimated that something like 1/500 of the population have a karyotype other than XX or XY. HealthyPlace.com reports that "since genetic testing was instituted for women in the Olympic Games, a number of women have been disqualified as 'not women,'after winning. However, none of the disqualified women was a man; all have atypical karyotypes, and one gave birth to a healthy child after having been disqualified."[8]

     Intersexuals are people who represent chromosomal, anatomical, and hormonal exceptions to the female/male dimorphic ideal. (Slide 19; ) The sex chromosomes determine the differentiation of the gonads into ovaries, testes, ovo-testes, or non-functioning tissues. The hormones produced by the fetal gonads determine the differentiation of the external genitalia into male, female, or intermediate morphology. Intersexual genitals may look nearly female, with a large clitoris, or with some degree of posterior labial fusion. Alternatively, they may look male, although the penis may be small. The genitalia may be mid-way between male and female with a phallic structure that could be considered either a large clitoris or a small penis. The external genitalia might be a split, empty scrotum. Alternatively, outer labia may be present with around a small vagina that opens into the urethra rather than into the perineum. In intersexuals, gender assignment, hormones, anatomy, psychological factors, etc. all converge to ultimately produce the sexual orientation of a person who may have genitalia of one or both genders. If you are interested in learning more about intersexuals, check out the Intersex Society of North America resource site on the web.

     Given that about 2% of people people born in the United States are intersexual, Anne Fausto-Sterling suggested in 1993 a five-sex system (perhaps five "gender" system would be more accurate) to acknowledge the fact that there is range of sexualities based on external genitalia and sexual orientation.[9] The table below describes the incidence of intersexuality in terms of the medical diagnosis. For our purposes here, it is really important to note the high incidence of intersexuality in the bottom two rows. (Slides 20 and 21; ) In addition to "female" and "male," Fausto-Sterling suggested three additional sexes: "herms" (people born with both a testes and an ovary); "merms" (males born with testes and some aspect of female genitalia); and "ferms" (females who possess ovaries and some aspect of male genitalia). In 2000, Dr. Fausto-Sterling published a follow up paper detailing her further work in this area of sexuality.[10] You can read these works on Dr. Fausto-Sterling's website.

How Common is Intersexuality?

     Surgery was the most common remedy formerly used to treat intersexuals. When presented with a baby with ambiguous genitalia, the medical team made a "gender assignment" based on what made the best surgical sense. Parents then raised their child based on the surgically assigned gender. However, time proved this program to be simplistic and in some cases catastrophic. Some individuals who were reassigned as males or females shortly after birth came to reject their surgically-defined assignments. However, other individuals were satisfied with the choice made for them by the surgical team.

(In May 2003, I wrote a small piece for The Communicant, the newsletter of St. Paul's Episcopal Church in which I summarized Dr. Fausto-Sterling's work and presented a theological interpretation of it in view of the creation story from Genesis. Some of the above is excerpted from that article.)

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Interpretations and Thoughts for Discussion

     The fact that people come in bewildering sexual varieties - which may be significantly influenced by innate factors - speaks directly to the awe-inspiring wonder and diversity of God's creation. We are called to honor and respect that creation in all of its forms. However, Stanton L. Jones points out that scientific findings from nature "are not decisive in the church's moral and ecclesiastical struggles over homosexuality." He continues, "The prevalence of a particular behavior pattern has no clear relevance to the moral evaluation of that patters; whether patterns are common (e.g., greed, pride, lust) or extremely unusual (e.g., cannibalism, necrophilia) bears no necessary relationship to its status as a moral evil."[11] Do you agree? (Slide 22; )

• What should the status of the sciences be in theological reflection?
• Is homosexuality a preference one chooses, or an orientation one discovers about oneself? What difference would this distinction make?
• Is there moral significance to the scientific discoveries we have discussed?

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COMMENTS? E-MAIL ME

Next Class (July 20): The spirituality and psychology of sexual expression (Slide 23; )

[1] Chandler Burr. "Homosexuality and Biology." Homosexuality in the Church: Both Sides of the Debate. Siker, Jeffrey S. (Ed.). Louisville, KY: Westminster John Knox Press. 1994). 116-134.

[2] Burr, 119-120.

[3] Swaab D, Hofman M. An enlarged suprachiasmic nucleus in homosexual men. Brain Res 537:141-148, 1990.

[4] LeVay, S. A Difference in the hypothalamic structure between heterosexual and homosexual men. Science 253:1034-1037, 1991; and Allen, L., and R. Gorski. Sexual orientation and the size of the anterior commisure in the human brain. Proc Nat Acad Sci (USA) 89:7199-7202, 1992.

[5] Goldstein JM, Seidman LJ, Horton NJ, Makris N, Kennedy DN, Caviness VS Jr, Faraone SV, Tsuang MT. Normal sexual dimorphism of the adult human brain assessed by in vivo magnetic resonance imaging. Cereb Cortex 11(6):490-7, 2001.

[6] Bailey, JM and RC Pillard. A genetic study of male sexual orientation. Arch Gen Psychiat 48:1089-1096, 1991.

[7] Bailey, J.M., et al. Heritable factors influence sexual orientation in women. Arch of Gen Psychiat 50:217-223, 1993.

[8] Copied at 2230 on 8 July 2003 from http://www.healthyplace.com/Communities/Gender/intersexuals/intersexuality_faq.htm.

[9] Fausto-Sterling, Anne. The Five Sexes. The Sciences (March/April) 1993 pp. 20-25.

[10] Fausto-Sterling, Anne. The Five Sexes, Revisited. The Sciences (July/August) 2000 pp. 18-23.

[11] Jones, Stanton L. and Don E. Workman. "Homosexuality: The Behavioral Sciences and the Church." Homosexuality in the Church: Both Sides of the Debate. Siker, Jeffrey S. (Ed.). Louisville, KY: Westminster John Knox Press. 1994), 108.

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