American Society of Naturalists

A membership society whose goal is to advance and to diffuse knowledge of organic evolution and other broad biological principles so as to enhance the conceptual unification of the biological sciences.

Letter to Secretary Azar on the Scientific Understanding of Sex and Gender

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The society has signed the letter below. If you wish to sign a letter individually, see

https://not-binary.org/statement/

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SECRETARY ALEX AZAR
DEPARTMENT OF HEALTH AND HUMAN SERVICES
HUBERT H. HUMPHREY BUILDING
200 INDEPENDENCE AVENUE SW., ROOM 445-G
WASHINGTON, DC 20201

RE: SCIENTIFIC UNDERSTANDING OF SEX AND GENDER

October 30, 2018

Dear Secretary Azar,                                   

As scientists, we write to express our concerns about the attempt by the Department of Health and Human Services (HHS) to claim that there is a biological basis to defining gender as a strictly binary trait (male/female) determined by genitalia at birth.

Variation in biological sex and in gendered expression has been well documented in many species, including humans, through hundreds of scientific articles. Such variation is observed at both the genetic level and at the individual level (including hormone levels, secondary sexual characteristics, as well as genital morphology). Moreover, models predict that variation should exist within the categories that HHS proposes as "male" and “female”, indicating that sex should be more accurately viewed as a continuum. Indeed, experiments in other organisms have confirmed that variation in traits associated with sex is more extensive than for many other traits. Beyond the incorrect claim that science backs up a simple binary definition of sex or gender, the lived experience of people clearly demonstrates that the genitalia one is born with do not define one's identity.

Diversity is a hallmark of biological species, including humans.  Our scientific societies represent over 3000 scientists, many of whom are experts on the variability that is found in sexual expression throughout the plant and animal kingdoms. If you wish to speak to one of our experts or receive peer-reviewed papers that explain why there is a continuum of sexual expression, please contact us at president@evolutionsociety.org.

Sincerely,

Dr. Hopi Hoekstra
President, Society for the Study of Evolution
Professor, Harvard University

Dr. Sharon Strauss
President, American Society of Naturalists
Professor, University of California, Davis

Dr. Susana Magallón
President, Society of Systematic Biologists
Professor, Universidad Nacional Autónoma de México