This SciShow video tells the story of Sue the T-Rex and the tricky task of determining the sex of fossilized animals using evidence.
Video: Menstruation by the Mahalingaiah Lab
This is a video created through Living Laboratory(c) at the Museum of Science Boston, in collaboration with the Mahalingaiah Lab at Harvard School of Public Health. It explains menstruation in a non-gendered, non-sexual way to inform young people about changes in their bodies
Other, Neither, Both - Talk by Sam Sharpe
Biological sex takes on so many diverse patterns across species, but discussion of human sex often consists of an oversimplified and incomplete binary. Biologist Sam Sharpe discussed this issue in a five-minute INSPIRE talk at the Ecological Society of America annual meeting in 2020.
Video: The Origin of Gender
This video, from the PBS “Origin of Everything” series, discusses the origins of gender in humans. The concept of gender is distinguished from biological sex, and the homology of sex organs is briefly discussed as it played a role in developing the concept of gender in some societies. Most of the video is spent how ideas of gender have developed through history in multiple cultures. We noted a valuable and rarely made distinction : the video discusses how the concept of “man” has often been closely associated with race and class, not just with gender.
TED Talk: "The way we think about biological sex is wrong" by Emily Quinn
Emily Quinn, an intersex activist, delivered this 14-minute talk at the TedWomen 2018 event. Emily tells her personal story and discusses the little-known truth that biological sex is a spectrum and not a binary. This is true whether we measure biological sex by chromosomes, hormones, gonads, or external genitalia. She dispels the myth of intersex people as extremely rare outliers, and humanizes diversity in biological sex.
It's rare to meet an intersex person that hasn't been operated on. Oftentimes, these surgeries are done to improve intersex kids' lives, but they usually end up doing the opposite, causing more harm and complications, both physical and emotional. I'm not saying that doctors are bad or evil. It's just that we live in a society that causes some doctors to "fix" those of us who don't fit their definition of normal. We're not problems that need to be fixed. We just live in a society that needs to be enlightened.
This video is uploaded to Youtube but its mature content tag makes it inaccessible through some school internet filters. Alternatively, TED.com page contains the video, transcript in 24 languages, and further reading list.
Video: One of a Kind
This is the second episode of the PBS documentary series “9 Months That Made You.” The episode uses family interviews, documentary footage, and computer animations to detail the relationship between genetic and phenotypic variations in humans. Among those featured is güevodoces, a specific intersex trait observed in the Dominican Republic. We felt that the individuals were portrayed with empathy and autonomy, and using modern language. As a post-viewing exercise, students may discuss the various choices of language used to describe variation within the episode.
The güevodoces clip can be streamed for free on Vimeo. The entire episode can be streamed for free on Kanopy with a public library card or university login. It is also available with a paid subscription on Netflix and PBS as of the time writing this post.
Neuroendocrinology (Sex & Gender) with Daniel Pfau: Interview on Ologies Podcast
In this 2020 episode, Ologies podcast host Alie Ward interviews genderqueer researcher Dr. Daniel Pfau. Dr. Pfau talks extensively about gender in biology, including queer behavior in animals, how hormones influence the brain, the variation of gender expression, how a strict gender binary is harmful to entire populations, hormone replacement therapy, and hormones in sports. The episode page includes streaming for Parts 1 and 2, as well as a transcript and show notes.
In 2024, Dr. Pfau returned for an encore episode!
Video: Are There "Male" and "Female" Brains?
This SciShow video reviews data concerning differences in the brains of biological males and biological females. The writers are careful to mention that research on this topic does not account for transgender or intersex individuals, and that neuroscience research as a whole is heavily focused on studying the brains of male humans and animals. You may also wish to discuss with students about the definition of “biological sex” and how that definition has changed throughout history.
Why does Homosexuality Evolve?
This video by Soliloquy outlines several hypotheses for why same-sex sexual behavior has persisted rather than becoming extinct in human and nonhuman species. Although not all of these hypotheses are supported by data, the video demonstrates how a behavior that appears deleterious to an individual can actually be neutral or beneficial when considering the complex social interactions within a population.
Video: What It's Like To Be Intersex
Image shows four intersex individuals smiling in front of a blue background.
In this video, four intersex individuals talk about the meaning of intersex, their personal identities, the difference between gender identity and biological characteristics, and "normalizing" surgery. In the biology classroom, this video is a way to supplement textbooks and other curricular resources that may pathologize and anonymize the topic of intersex traits.
Video: Touch-Based Sex Determination in Slipper Limpets
Image shows several slipper limpets (small snail-like organisms) with four captions reading (1) A larva that settles on an unoccupied substrate develops into a female, which produces chemicals that attract other larvae. (2) The larvae attracted by the female settle on top of her and develop into males, which become mates for the original female. (3) Eventually the males on top switch sex, developing into females. (4) They then attract additional larvae, which settle on top of the stack and develop into males. This image is from Genetics: A Conceptual Approach, Fourth Edition.
Slipper limpets are unique because their sexual development is influenced by touch with other individuals of the same species. Maryna Lesoway from the University of Illinois at Urbana Champaign concisely explains current research on the phenomenon.
Video: Intersex Across the Animal Kingdom
This SciShow video reviews several intersex traits in humans and several patterns of hermaphroditism in animal species. At different times in the video, the host describes this phenomenon as a “condition,” “disorder,” and “variation”. You may wish to discuss the impact of these word choices with your students.
Editor’s note: The term "hermaphrodite" is appropriate for referring to non-human animals with sex characteristics that do not fit typical binary notions of male or female bodies. For humans, “intersex” is the appropriate term—learn more here!
Video: Secrets of the X chromosome
This TED-Ed video by Robin Ball comes with a small set of questions to be used in a lesson. The gendered language and visuals used in the video are more nuanced than most.
Video: There Are More Than Two Human Sexes
This SciShow video summarizes the complexity of human sex determination, which often wrongly thought to be binary. Mosaicism, chimerism, and intersex traits and nonconsensual surgeries are mentioned.
Video: The Crocodile's Unusual Sex-Determination System Explained
This video from Facts in Motion illustrates how the sex of crocodiles is determined by environment and not genetics. The sex ratio of developing crocodile eggs is shown to be a function of temperature, thought to be mediated by a thermosensor protein. Climate change may impact or even cause the extinction of crocodile populations.
This sex-determination system is not so “unusual” because it occurs in other reptiles and fish species. But it is certainly interesting and gathering attention. The College Board’s 2018 AP Biology exam had a free response question about temperature-dependent sex determination in fish.