Perry et al v. Schwarzenegger et al

Filing 379

Brief re 377 MOTION to File Amicus Curiae Brief filed byPaul R. McHugh. (Related document(s) 377 ) (Schweickert, Christopher) (Filed on 1/8/2010)

Perry et al v. Schwarzenegger et al Doc. 379 Case3:09-cv-02292-VRW Document379 Filed01/08/10 Page1 of 12 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 Steven N.H. Wood, Esq. (CA SBN 161291) Christopher J. Schweickert, Esq. (CA SBN 225942) BERGQUIST, WOOD & ANDERSON, LLP 1470 Maria Lane, Suite 300 Walnut Creek, CA 94596 Telephone: (925) 938-6100 Facsimile: (925) 938-4354 wood@wcjuris.com cjs@wcjuris.com Attorneys for Amicus Curiae Paul R. McHugh, M.D. UNITED STATES DISTRICT COURT NORTHERN DISTRICT OF CALIFORNIA KRISTIN M. PERRY, et al., Plaintiffs, and CITY AND COUNTY OF SAN FRANCISCO, Plaintiff-Intervenor, v. ARNOLD SCHWARZENEGGER, et al., and Defendants, CASE NO. 09-CV-2292 VRW BRIEF OF AMICUS CURIAE PAUL R. MCHUGH, M.D. IN SUPPORT OF DEFENDANT-INTERVENORS Date: Time: Location: Judge: Trial Date: To Be Determined By The Court To Be Determined By The Court Courtroom 6, 17th Floor Chief Judge Vaughn R. Walker January 11, 2010 PROPOSITION 8 OFFICIAL PROPONENTS DENNIS HOLLINGSWORTH, GAIL J. KNIGHT, MARTIN F. GUTIERREZ, HAKSHING WILLIAM TAM, and MARK A. JANSSON; and PROTECTMARRIAGE.COM ≠ YES ON 8, A PROJECT OF CALIFORNIA RENEWAL, Defendant-Intervenors. BRIEF OF AMICUS CURIAE PAUL R. MCHUGH, M.D. IN SUPPORT OF DEFENDANT-INTERVENORS CASE NO. 09-CV-2292 VRW Dockets.Justia.com Case3:09-cv-02292-VRW Document379 Filed01/08/10 Page2 of 12 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 II. B. C. D. TABLE OF CONTENTS TABLE OF AUTHORITIES ........................................................................................................ ii INTEREST OF AMICUS CURIAE................................................................................................1 INTRODUCTION .........................................................................................................................1 I. THERE IS NO SCIENTIFIC AGREEMENT ON THE DEFINITION OF HOMOSEXUALITY...........................................................................................................1 A. There is significant disparity within even the most commonly-used definitions of orientation.............................................................................................2 Sexual orientation changes over time .........................................................................3 The definition of "homosexual" is even broader than conduct, attraction, or self-identity ...........................................................................................4 The definitional gap results in a hugely significant difference in the number of class members............................................................................................5 EMERGING EVIDENCE SUGGESTS THAT HOMOSEXUALITY IS NOT AN INNATE CHARACTERISTIC LIKE RACE OR SEX................................................6 CONCLUSION..............................................................................................................................7 i BRIEF OF AMICUS CURIAE PAUL R. MCHUGH, M.D. IN SUPPORT OF DEFENDANT-INTERVENORS CASE NO. 09-CV-2292 VRW Case3:09-cv-02292-VRW Document379 Filed01/08/10 Page3 of 12 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 TABLE OF AUTHORITIES J.M. Bailey, et al., Heritable Factors Influence Sexual Orientation in Women, 50 ARCHIVES OF GEN. PSYCHIATRY 217 (1993)........................................................................6 J.M. Bailey & R.C. Pillard, A Genetic Study of Male Sexual Orientation, 48 ARCHIVES OF GEN. PSYCHIATRY 1089 (1991)......................................................................6 Peter S. Bearman & Hannah Bruckner, Opposite-Sex Twins and Adolescent Same-Sex Attraction, 107 AM. J. OF SOCIOLOGY 1179 (2002) .........................................................6, 7 Gail S. Bernstein, Ph.D., Defining Sexual Orientation, SELFHELP MAGAZINE, http://www.selfhelpmagazine.com/article/sexual_orientation.........................................1, 2 Karen L. Bridges and James M. Croteau, Once-Married Lesbians: Facilitating Changing Life Patterns, 73 J. OF COUNSELING AND DEV. 134 (Nov./Dec. 1994) ....................................................................................................................................4 Christopher Carpenter & Gary Gates, Gay and Lesbian Partnership: Evidence from California, 45 DEMOGRAPHY 573 (2008) ...........................................................................2 JOHN P. DECECCO, GAY PERSONALITY AND SEXUAL LABELING (1985) .....................................4, 5 LOUIS DIAMANT AND RICHARD D. MCANULTY, THE PSYCHOLOGY OF SEXUAL ORIENTATION, BEHAVIOR, AND IDENTITY: A HANDBOOK 82 (1995) ..................................3 Lisa M. Diamond, New Paradigms for Research on Heterosexual and Sexual Minority Development, 32 (4) J. OF CLINICAL CHILD AND ADOLESCENT PSYCHOL. 492 (2003) ...........................................................................................................1 Lisa M. Diamond & Ritch C. Savin-Williams, Explaining Diversity in the Development of Same-Sex Sexuality Among Young Women, 56 J. OF SOC. ISSUES 297 (2000) ................................................................................................................3 Lisa M. Diamond, Sexual Identity, Attractions, and Behavior Among Young SexualMinority Women Over a 2-Year Period, 36 DEVELOPMENTAL PSYCHOL. 241 (2000)...................................................................................................................................3 E. Eckert, et al., Homosexuality in monozygotic twins reared apart, 148 British J. Psychiatry 421 (1986) ..........................................................................................................6 RICHARD C. FRIEDMAN AND JENNIFER I. DOWNEY, SEXUAL ORIENTATION AND PSYCHOANALYSIS: SEXUAL SCIENCE AND CLINICAL PRACTICE 39 (2002) ..........................6 John C. Gonsiorek, et al., Definition and Measurement of Sexual Orientation, in SUICIDE AND LIFE-THREATENING BEHAVIOR 40 (1995) .................................................4, 5 Kenneth S. Kendler, et al., Sexual Orientation in a U.S. National Sample of Twin and Nontwin Sibling Pairs, 157 AM. J. OF PSYCHIATRY 1843 (2000) ....................................6, 7 Michael King & Elizabeth McDonald, Homosexuals who are Twins, 160 British J. Psychiatry 407 (1992) ......................................................................................................6, 7 ii BRIEF OF AMICUS CURIAE PAUL R. MCHUGH, M.D. IN SUPPORT OF DEFENDANT-INTERVENORS CASE NO. 09-CV-2292 VRW Case3:09-cv-02292-VRW Document379 Filed01/08/10 Page4 of 12 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 Niklas Langstrom, et al., Genetic and Environmental Effects of Same-Sex Sexual Behavior: A Population of Twins in Sweden, Arch.Sexual Behav. (Forthcoming) ......................................................................................................................6 Fritz Klein, Barry Sepekoff, and Timothy Wolf, Sexual Orientation: A Multi-Variable Dynamic Process, 11 (1) J. OF HOMOSEXUALITY 35 (1985) ...............................................4 EDWARD O. LAUMANN, ET AL., THE SOCIAL ORGANIZATION OF SEXUALITY (1994) ...................2, 5 A.E. MOSES & R.O. HAWKINS, JR., COUNSELING LESBIAN WOMEN AND GAY MEN: A LIFE ISSUES APPROACH 43 (1982)........................................................................................2 TIMOTHY F. MURPHY, GAY SCIENCE: THE ETHICS OF SEXUAL ORIENTATION RESEARCH 15 (1997) ...........................................................................................................4 TODD A. SALZMAN & MICHAEL G. LAWLER, THE SEXUAL PERSON 65 (2008) ............................1, 4 RITCH C. SAVIN-WILLIAMS, THE NEW GAY TEENAGER (2005) ......................................................2 Ritch C. Savin-Williams, Then and Now: Recruitment, Definition, Diversity, and Positive Attributes of Same-Sex Populations, 44:1 DEV. PSYCHOL. 135 (2008)..................2 Ritch C. Savin-Williams, Who's Gay? Does it Matter?, 15 CURRENT DIRECTIONS PSYCHOL. SCI. 40 (2006) .....................................................................................................2 M.G. Shively and J.P. DeCecco, Components of Sexual Identity, 3 J. HOMOSEXUALITY 41 (1977). ................................................................................................2 Robert L. Spitzer, Can Some Gay Men and Lesbians Change Their Sexual Orientation? 200 Participants Reporting a Change from Homosexual to Heterosexual Orientation, 32 ARCHIVES OF SEXUAL BEHAV. 403 (2003)...........................4 Joseph P. Stokes, et al, Predictors of Movement Toward Homosexuality: A Longitudinal Study of Bisexual Men, 43 J. OF SEX RES. 304 (1997)....................................3 iii BRIEF OF AMICUS CURIAE PAUL R. MCHUGH, M.D. IN SUPPORT OF DEFENDANT-INTERVENORS CASE NO. 09-CV-2292 VRW Case3:09-cv-02292-VRW Document379 Filed01/08/10 Page5 of 12 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 I. THERE IS NO INTEREST OF AMICUS CURIAE Amicus is a scholar of psychiatry with a professional interest in orientation issues. He seeks to provide information to this Court bearing on its decision of whether to endorse a legal declaration that orientation is a fixed and immutable characteristic similar to race or gender. INTRODUCTION Plaintiffs assert a claim on behalf of a larger group and claim that this group as a class has been denied liberty and equality. Thus, they urge comparisons to racial minorities and women who have been the victims of discrimination based on largely immutable group characteristics. As an expert in psychiatry, Amicus offers scientific information that is directly relevant to this court in assessing whether orientation as a category is sufficiently similar to race and gender to merit analogous treatment in Constitutional law. Amicus points out two highly relevant facts: (1) there is no scientific consensus on what homosexuality is, and the number of people who fit in the class "gay and lesbian" varies widely, depending on which definition of homosexuality is used and (2) there is no scientific consensus that homosexuality is exclusively or primarily genetic in origin. In fact, the most recent studies on identical twins cast increasing doubt on genetic explanations as primary reasons for sexual orientation. In the absence of a social and scientific consensus that orientation is an immutable or fixed class, laws defining marriage as a union of male and female should not trigger strict scrutiny on the grounds they deny marriage rights to a fixed class. SCIENTIFIC AGREEMENT ON THE DEFINITION OF HOMOSEXUALITY. "There is currently no scientific or popular consensus . . . that definitively `qualify' an individual as lesbian, gay, or bisexual." Lisa M. Diamond, New Paradigms for Research on Heterosexual and Sexual Minority Development, 32 (4) J. OF CLINICAL CHILD AND ADOLESCENT PSYCHOL. 492 (2003). "Much of the confusion about sexual orientation occurs because there is no single agreed upon definition of the term. . . . There is no one universally accepted definition of sexual orientation, nor of who is bisexual, lesbian, or gay." Gail S. Bernstein, Ph.D., Defining Sexual Orientation, SELFHELP MAGAZINE, http://www.selfhelpmagazine.com/article/sexual_ orientation. "The meaning of the phrase `sexual orientation' is complex and not universally agreed upon." TODD A. SALZMAN & MICHAEL G. LAWLER, THE SEXUAL PERSON 65 (2008). 1 BRIEF OF AMICUS CURIAE PAUL R. MCHUGH, M.D. IN SUPPORT OF DEFENDANT-INTERVENORS CASE NO. 09-CV-2292 VRW Case3:09-cv-02292-VRW Document379 Filed01/08/10 Page6 of 12 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 Nearly all studies of orientation describe the difficulty in defining the population of homosexuals. The authors of the "Chicago Sex Survey," which is considered one of the most reliable scholarly efforts to determine sexual practices in the United States, noted the following: [The authors' research] raises quite provocative questions about the definition of homosexuality. While there is a core group (about 2.4 percent of the total men and about 1.3 percent of the total women) in our survey who define themselves as homosexual or bisexual, have same-gender partners, and express homosexual desires, there are also sizable groups who do not consider themselves to be either homosexual or bisexual but have had adult homosexual experiences or express some degree of desire. EDWARD O. LAUMANN, ET AL., THE SOCIAL ORGANIZATION OF SEXUALITY 300-301 (1994). Other researchers report similar definitional complexities, e.g. "There is a physical orientation, an affectional orientation, and a fantasy orientation, with each of those three further divided into a past (historical) component and a present component. A person's behavior may be totally at variance with all aspects of orientation, and the various parts of orientation may not all agree." A.E. MOSES & R.O. HAWKINS, JR., COUNSELING LESBIAN WOMEN AND GAY MEN: A LIFE ISSUES APPROACH 43 (1982). A. There is significant disparity within even the most commonly-used definitions of orientation. Scientific literature includes at least three basic definitions of orientation, based on (a) sexual behavior, (b) sexual attraction, or (c) self-ascribed social identity. LAUMANN, supra at 291. See also Ritch C. Savin-Williams, Then and Now: Recruitment, Definition, Diversity, and Positive Attributes of Same-Sex Populations, 44:1 DEV. PSYCHOL. 135-38 (2008); M.G. Shively and J.P. DeCecco, Components of Sexual Identity, 3 J. HOMOSEXUALITY 41-48 (1977). Within each These definitional category there are significant subvariations. These are not minor variations on a theme. Rather, they present fundamentally different ways of understanding who is "gay." differences produce large variations in estimates of who counts as a member of this class. See LAUMANN, supra at 294-295, 297; RITCH C. SAVIN-WILLIAMS, THE NEW GAY TEENAGER (2005); Ritch C. Savin-Williams, Who's Gay? Does it Matter?, 15 CURRENT DIRECTIONS PSYCHOL. SCI. 40 (2006); Savin-Williams, Then and Now, supra at 135-38; Bernstein, supra; Christopher Carpenter & Gary Gates, Gay and Lesbian Partnership: Evidence from California, 45 DEMOGRAPHY 573, 574 (2008). 2 BRIEF OF AMICUS CURIAE PAUL R. MCHUGH, M.D. IN SUPPORT OF DEFENDANT-INTERVENORS CASE NO. 09-CV-2292 VRW Case3:09-cv-02292-VRW Document379 Filed01/08/10 Page7 of 12 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 B. Sexual orientation changes over time. The fluid nature of homosexuality is also fundamentally different from race and gender classifications. Even with an agreed-on definition of who falls into a homosexual class, this court should consider that its members are likely to move in and out of the class throughout their lives. "Contrary to the notion that most sexual minorities undergo a one-time discovery of their true identities, 50% of [a study's] respondents had changed their identity label more than once since first relinquishing their heterosexual identity." Lisa M. Diamond & Ritch C. Savin-Williams, Explaining Diversity in the Development of Same-Sex Sexuality Among Young Women, 56 J. OF SOC. ISSUES 301 (2000). In another study, the author notes that "[h]alf of the young women in this sample relinquished the first sexual-minority identity they adopted." Lisa M. Diamond, Sexual Identity, Attractions, and Behavior Among Young Sexual-Minority Women Over a 2-Year Period, 36 DEVELOPMENTAL PSYCHOL. 247 (2000). Although research into the origins of orientation is in its infancy, the research we have shows flux in adults' own self-ascription of homosexuality. That is, research that asks individuals to rate themselves on the homosexuality continuum, and then asks these same individuals to rate themselves again several months or years later, finds that many individuals vary, with some becoming more "gay" and some becoming less "gay" in their own estimation over time. "[W]e realize that homosexuality is not some monolithic construct one moves toward or from in a linear way; movement toward homosexuality fails to capture the fluid and contextual nature of sexuality. We also acknowledge that changes in sexual feelings and orientation over time occur in all possible directions." Joseph P. Stokes, et al, Predictors of Movement Toward Homosexuality: A Longitudinal Study of Bisexual Men, 43 J. OF SEX RES. 304, 305 (1997). The behavior/attraction/self-identification dimensions "suggest[] that sexual orientation is not static and may vary throughout the course of a lifetime." LOUIS DIAMANT AND RICHARD D. MCANULTY, THE PSYCHOLOGY OF SEXUAL ORIENTATION, BEHAVIOR, AND IDENTITY: A HANDBOOK 82 (1995). Scholars of orientation are also beginning to find an increasing number of women who insist that their self-identity as lesbians is in fact a personal choice, rather than a biological constraint. One study notes that "variability in the emergence and expression of female same-sex desire during the life course is normative rather than exceptional." Diamond & Savin-Williams, supra at 298. See also Diamond, Sexual Identity, supra. Other researchers report similar results. For example, researchers Charbonneau and Lander interviewed 30 women who had spent half their lives as heterosexuals, married, had 3 BRIEF OF AMICUS CURIAE PAUL R. MCHUGH, M.D. IN SUPPORT OF DEFENDANT-INTERVENORS CASE NO. 09-CV-2292 VRW Case3:09-cv-02292-VRW Document379 Filed01/08/10 Page8 of 12 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 children, and then in midlife became lesbian. Some of these women explained their lesbianism as a process of self-discovery. But a "second group of women . . . regarded their change more as a choice among several options of being lesbian, bisexual, celibate or heterosexual." Karen L. Bridges and James M. Croteau, Once-Married Lesbians: Facilitating Changing Life Patterns, 73 J. OF COUNSELING AND DEV. 134, 135 (1994) (describing C. Charbonneau and P.S. Lander, AT Redefining Sexuality: Women Becoming Lesbian in Mid-Life, in LESBIANS Sang, et al. ed., 1991)). MID-LIFE 35 (B. In addition to these sources of flux, recent scientific research shows that at least some strongly motivated individuals can change their orientation, in terms of identity, behavior, and selfreported sexual attraction. Robert L. Spitzer, Can Some Gay Men and Lesbians Change Their Sexual Orientation? 200 Participants Reporting a Change from Homosexual to Heterosexual Orientation, 32 ARCHIVES OF SEXUAL BEHAV. 403 (2003). If true, at what point does a person leave the class? And when does the person become ineligible for benefits or considerations offered to the class? These unavoidable questions add yet another dimension to the multi-faceted complexity of defining homosexuality. C. The definition of "homosexual" is even broader than conduct, attraction, or self-identity. The definitional complexity is not limited to only three definitions -- conduct, attraction, or self-identity -- and their subvariations. Some researchers believe that "sexual orientation cannot be reduced to a bipolar or even a tripolar process, but must be recognized within a dynamic and multi-variate framework." Fritz Klein, Barry Sepekoff, and Timothy Wolf, Sexual Orientation: A Multi-Variable Dynamic Process, 11 (1) J. OF HOMOSEXUALITY 35-49 (1985). Others recommend the use of a seventeen question, multiple subpart test to measure sexual orientation. John C. Gonsiorek, et al., Definition and Measurement of Sexual Orientation, in SUICIDE AND LIFE- THREATENING BEHAVIOR 40 (1995). And others, with the caveat that "the concept of sexual orientation is a product of contemporary Western thought," apply their own specific definition for their current research purpose. TIMOTHY F. MURPHY, GAY SCIENCE: THE ETHICS ORIENTATION RESEARCH 15-24 (1997). "[T]he categories of homosexual, gay, and lesbian do not signify a common, universal experience." SALZMAN, supra at 2. Because there is no common experience, many will argue for an ever-broadening definition of who belongs in a sexual orientation class. "It will be useful to expand our notions of sexual orientation to include more than just bisexuality, heterosexuality and homosexuality. . . . With respect to various components of sexual orientation, an individual may be 4 BRIEF OF AMICUS CURIAE PAUL R. MCHUGH, M.D. IN SUPPORT OF DEFENDANT-INTERVENORS CASE NO. 09-CV-2292 VRW OF SEXUAL Case3:09-cv-02292-VRW Document379 Filed01/08/10 Page9 of 12 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 heterosexual, homosexual, bisexual, as well as fetishistic, transvestitic, zoophiliac, and so on. It is important to note that these are not mutually exclusive categories." JOHN P. DECECCO, GAY PERSONALITY AND SEXUAL LABELING 16 (1985). Under this rationale, the population of a homosexual class might plausibly include most of society. The broad spectrum of definitional possibilities could lead one to "conclude there is serious doubt whether sexual orientation is a valid concept at all. Social constructionism suggests that there is nothing `real' about sexual orientation except a society's construction of it." Gonsiorek, supra at 4. D. The definitional gap results in a hugely significant difference in the number of class members. How much difference do varying definitions of homosexuality make? The 2000 Census reports 12,130,354 men and 12,491,465 women over 18 in California. Applying the Chicago Sex Survey's proportions, if Californians are defined as gay by self-identification as either gay or bisexual, 339,650 men and 174,881 women in the state are gay or lesbian (based on reports that "2.8 percent of the men and 1.4 percent of the women" surveyed in the U.S. "reported some level of homosexuality (or bisexual) identity" LAUMANN, supra at 293). If homosexuality is defined by sexual attraction, however, the numbers would increase to 545,865 for men and 699,520 for women. LAUMANN, supra at 297. Who is gay in California? The number of men varies from 340,000 to 546,000 and the number of women varies from 175,000 to 700,000, depending on the definition used. Thus, the class of people who are gay and lesbian may more than double or be cut by more than half, depending on which equally scientifically legitimate and commonly used definition is applied. The absence of any scientific or social agreement about who is included as a homosexual, and evidence of at least some flux in self-ascription over time, makes orientation fundamentally different in nature than race or gender. II. EMERGING EVIDENCE SUGGESTS THAT HOMOSEXUALITY IS NOT AN INNATE CHARACTERISTIC LIKE RACE OR SEX. Many people believe that homosexuality is genetic in origin, and therefore structurally similar to race or gender. There is, however, no scientific consensus that homosexuality is exclusively or primarily genetic in origin. Recent scientific research and opinion indicates that 5 BRIEF OF AMICUS CURIAE PAUL R. MCHUGH, M.D. IN SUPPORT OF DEFENDANT-INTERVENORS CASE NO. 09-CV-2292 VRW Case3:09-cv-02292-VRW Document379 Filed01/08/10 Page10 of 12 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 genetics is not the primary explanation. As two Columbia University sociologists suggest in a recent study, the efforts to establish genetic or hormonal effects on sexual orientation have been "inconclusive at best." Peter S. Bearman & Hannah Bruckner, Opposite-Sex Twins and Adolescent Same-Sex Attraction, 107 AM. J. OF SOCIOLOGY 1179, 1180 (2002). Two other scholars recently said that ". . . the assertion that homosexuality is genetic is so reductionistic that it must be dismissed out of hand as a general principle of psychology." What, then, causes homosexuality? It is apparent that biological, psychological and social factors PSYCHOANALYSIS: SEXUAL SCIENCE interacting in complex and various ways shape human sexual orientation. RICHARD C. FRIEDMAN AND JENNIFER I. DOWNEY, SEXUAL ORIENTATION AND AND CLINICAL PRACTICE 39 (2002). Identical twin studies are used to tease out the genetic component of behaviors. The evidence from these studies is mixed. See, e.g., K. Kendler, et al., Sexual Orientation in a U.S. National Sample of Twin and Nontwin Sibling Pairs, 157 Am. J. Psychiatry 1845 (2000) (finding a genetic component of homosexuality); E. Eckert, et al., Homosexuality in monozygotic twins reared apart, 148 British J. Psychiatry 421 (1986) (finding no genetic component of homosexuality); J. Michael Bailey, et al., Genetic & Environmental Influences on Sexual Orientation & its Correlates in an Australian Twin Sample, 78 J. Personality & Soc. Psychol. 524 (2000) (finding no genetic component of homosexuality). But the most recent and best identical twins study using large, nationally representative data found no evidence of any genetic influence at all, furthering a recent trend in scientific research on orientation of rejecting genetic explanations as primary. For example, 1991 and 1993 studies, involving twin pairs recruited through homosexual publications, reported a concordance rate (similarity across the twins) of approximately 50 percent, which would suggest some heritable influence. J.M. Bailey, et al., Heritable Factors Influence Sexual OF Orientation in Women, 50 ARCHIVES GEN'L PSYCHIATRY 217 (1993); J.M. Bailey & R.C. OF Pillard, A Genetic Study of Male Sexual Orientation, 48 ARCHIVES GEN'L PSYCHIATRY 1089 (1991). But a 50 percent concordance rate among identical twins does not suggest that genetic influences are primary, since it is illogical to conclude that if one twin was gay, that 100 percent of other identical twins are gay. Other twin studies support this conclusion. See Niklas Langstrom, et al., Genetic and Environmental Effects of Same-Sex Sexual Behavior: A Population of Twins in Sweden, Arch.Sexual Behav. (forthcoming) (finding genetic effects explained .34-.39 of the variance in men and .18-.19 of the variance in women and concluding that "same-sex behavior arises not only from heritable but also from individual specific environmental sources."); Michael 6 BRIEF OF AMICUS CURIAE PAUL R. MCHUGH, M.D. IN SUPPORT OF DEFENDANT-INTERVENORS CASE NO. 09-CV-2292 VRW Case3:09-cv-02292-VRW Document379 Filed01/08/10 Page11 of 12 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 King & Elizabeth McDonald, Homosexuals who are Twins, 160 British J. Psychiatry 407, 409 (1992) (finding a striking "discordance for sexual orientation in both monozygotic and dizygotic pairs . . . [that] confirms that genetic factors are insufficient explanation of the development of sexual orientation" and concluding "[i]t is clear that our current genetic and psychological theories are untenable. The co-twins of men and women who identify themselves as homosexual appear to have a potential for a range of sexual expression."). Moreover, sociologists Bearman and Bruckner point out that using common heritability estimates suggests that many voluntary social actions are the result of genetic influence. In explanation, they note a study that suggests "substantial heritability for caring for tropical fish (28%), and frequency of various behaviors such as purchasing folk music in the past year (46%), chewing gum (58%), and riding a taxi (38%)." Bearman & Bruckner, supra at 1185 note 8. A small-scale study published in 2000 showed even lower concordance rates of 31.6 percent. Kenneth S. Kendler, et al., Sexual Orientation in a U.S. National Sample of Twin and Nontwin Sibling Pairs, 157 AM. J. OF PSYCHIATRY 1843, 1845 (2000) (sample of nineteen pairs). Identical twin studies suffer from some of the same recruitment problems that other nonprobability or "convenience" samples face. Identical twins who are more alike are more likely to volunteer for identical twin registries, for example, and some studies rely on twin's estimates of their twin's orientation, which have been shown to be unreliable. Columbia professors Bearman and Bruckner note that "[a]s samples become more representative, concordance on sexual behavior, attraction, and orientation, as expected, declines." Bearman & Bruckner, supra at 1184. Their own study focused on "same-sex romantic attraction" in a large, nationally representative sample (the Add-Health database, which is representative of all teens in schools in the late 1990s). This study found no noticeable pattern suggesting genetic influence at all. Concordance rates for identical twins were only 6.7 percent, which was about the same as the 7.2 percent found for fraternal twins. Id. at 1197-1198. They concluded: "[W]e find no support for genetic influences on same-sex preference net of social structural constraints. . . .Finally, we find substantial indirect evidence in support of a socialization model at the individual level." Id. at 1199. There is no scientific consensus that orientation is exclusively or primarily genetic in origin. This makes orientation fundamentally different in character from race or gender. 7 BRIEF OF AMICUS CURIAE PAUL R. MCHUGH, M.D. IN SUPPORT OF DEFENDANT-INTERVENORS CASE NO. 09-CV-2292 VRW Case3:09-cv-02292-VRW Document379 Filed01/08/10 Page12 of 12 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 CONCLUSION Society is rapidly moving towards greater acceptance of and accommodations for the legitimate social needs of gay and lesbian individuals. It would be a mistake for the court to freeze into law a view of sexual orientation that does not hold up under current scientific scrutiny and may well not hold up under future scientific scrutiny. Many gay people, especially lesbians, are clearly asserting their right to a homosexual identity as a matter of choice, not genes, and recent scientific research support their conclusion that, in this respect, homosexuality is not analogous to race or gender. We suggest that it would be inappropriate for this court to conclude that strict scrutiny is needed to protect orientation as a class, or to mandate a redefinition of marriage when no scientific or social consensus exists on the nature, membership and characteristics of the class claiming discrimination. Respectfully submitted, Dated: January 8, 2010 /s/ ____________________________________________ Steven N.H. Wood, Esq. (CA SBN 161291) Christopher J. Schweickert, Esq. (CA SBN 225942) BERGQUIST, WOOD & ANDERSON, LLP 1470 Maria Lane, Suite 300 Walnut Creek, CA 94596 Telephone: (925) 938-6100 Facsimile: (925) 938-4354 wood@wcjuris.com cjs@wcjuris.com Attorneys for Amicus Curiae Paul R. McHugh, M.D. 8 BRIEF OF AMICUS CURIAE PAUL R. MCHUGH, M.D. IN SUPPORT OF DEFENDANT-INTERVENORS CASE NO. 09-CV-2292 VRW