Mount Holyoke Professor Patty Brennan receives lifetime honor for genital morphology research

Professor Patty Brennan was elected an American Association for the Advancement of Science Fellow for her contributions to biological research. Photo couretsy of Patty Brennan.

By Catelyn Fitzgerald ’23

Science and Environment Editor

A comic posted outside of Mount Holyoke Professor Patty Brennan’s office depicts two ducks going on a dinner date.  As the female duck excitedly chatters about the latest avian gossip — old men tossing bread, close encounters with dogs — the male duck is distracted by a more pragmatic thought: “Oh my god. Your vagina better spiral in the same direction as my penis or I am out.”

Brennan is an associate professor of biological sciences whose research focuses on the evolution of genital morphology in animals, according to the Mount Holyoke College website. In Jan. 2023, Brennan was elected as a Fellow of the American Association for the Advancement of Science, a lifetime award granted to “scientists, engineers and innovators from around the world” in recognition of the contributions to society made throughout their careers, according to AAAS. The AAAS Fellow award dates back to 1874, with previous honorees including W.E.B. DuBois, the “founding father of American sociology,” and Ellen Ochoa, a former astronaut and the first Hispanic director of the Johnson Space Center, states their website. According to the College, Brennan was one of over 500 Fellows elected to the 2022 class. “I’m actually really excited about it because I love AAAS,” she said of the award, adding that she has been a member of the organization since grad school.

Brennan’s interest in biology came long before her emergence into the field of genital morphology. She studied the cardiac function of marine animals at the Universidad de Bogotá Jorge Tadeo Lozano in Bogotá, Colombia, and later went on to spend two years on a research boat traveling around the Galapagos Islands and Costa Rica. She then completed a doctorate at Cornell University, where her research largely focused on birds. She explained that upon starting the program she was less familiar with avian research, but was drawn to the field by an opportunity to study a group of birds in her home country of Colombia. Brennan had no idea at the time, but this group of birds was one of the few species that have penises, which would ultimately shape the direction of her career, she said. “When I watched them mating, I saw the penis and I realized,” she said of her discovery of the birds’ genitalia. “I thought it was so weird,” she continued. This initial glimpse into the world of avian genital morphology made her realize how little was known about the subject, and she resolved to investigate it further. 

Morphology, in a biological context, refers to “the study of the size, shape and structure of animals, plants and microorganisms and of the relationships of their constituent parts,” according to Encyclopedia Britannica. Brennan’s research has explored genital morphology throughout the animal kingdom. The diversity of animals found in Brennan’s studies is a product of her opportunistic research style. She explained that she reaches out to other labs in search of animal carcasses, and begins a study once she has enough specimens to work on. She remarked that it is relatively easy to obtain specimens, as most focus on parts of animals other than the genitalia, “in fact I have three freezers full of dead things downstairs,” she said with a laugh.

In the early days of her research, she discovered that female ducks have complex vaginas, which tells a “story of sexual conflict in genitalia,” she said. Sexual conflict is a common theme throughout Brennan’s research. The term describes when male and female members of a species have opposing reproductive interests, she explained. While both feel the biological urge to reproduce and advance the survival of their species, males and females may “disagree on the details,” such as who cares for the offspring. These differences are not expressed over a bread basket in a nice restaurant, as the comic outside Brennan’s office may suggest, but through the evolution of their genitalia. Genital morphology has evolved in a variety of ways in response to sexual conflict, Brennan explained, from mechanisms in females’ vaginas that prevent the entrance of an unwanted male, to penile spines that injure females during procreation, delaying future procreation until they are healed. “For ducks, it is about where the sperm ends up,” she said. 

According to a 2009 study conducted by Brennan and other researchers at Yale University, ducks have unique corkscrew-shaped genitalia with an important difference between the sexes — while females have vaginas that spiral in a clockwise direction, males’ penises spiral counterclockwise. This is an example of “sexually antagonistic genital coevolution” which is when “the sexes evolve traits that allow them to control the outcome of fertilization,” the study said. The study found that the opposing morphology of the male and female genitalia can prevent the penis from fully entering the vagina in situations of unwanted copulation. As a result, the male duck’s sperm is deposited farther from the ovaries during forced copulation, helping the female avoid an unwanted pregnancy. “I was surprised that this was something that was not already known,” she said of the female’s unique anatomy, adding that she then wanted to see if her discovery applied to other species, leading to a wealth of new research on the genital morphology of other animals including bats, snakes and dolphins.

Another focus of Brennan’s research is clitoris morphology. According to ResearchGate, her publications on the subject include the first “complete description” of the snake clitoris and a study that suggests the presence of functional clitorises in dolphins. “I think that it is asking about pleasure, and the evolution of pleasure and the importance of pleasure,” she said of her research. She added that she aims to improve the understanding of human pleasure through her work and disrupt the notion that “everyone expects that sex will be pleasurable for males, but females not so much”, commenting that issues related to pleasure are often ignored “as long as [the individual] can still get pregnant.” 

Her research in vaginal biomechanics, which investigates the diversity found in vaginal structures, comes from a similar motivation. This diversity plays an important role in the study of the human vagina. She offered the example of research on the effects of birth on the human vagina, which is often done using rat vaginas despite their major morphological dissimilarities. Brennan hopes to use her research on biomechanic diversity to find better subjects to inform human-centered research. “I am looking at other models that we can use to look at what happens to the vagina when it is stressed during birth,” she said.

Brennan’s research has been the subject of much excitement from the public and in the media. “People love stories of weird animal sex,” she said, adding that each new discovery is “something that we should have known but we didn’t for some reason.” Brennan does not shy away from the intrigue. “It’s one of the best parts of my research, being able to do outreach,” she said. She is also an advocate for basic science. Basic science, unlike applied science, does not attempt to address a particular issue, but instead evolves out of curiosity and a desire to expand scientific knowledge, an NPR article about Brennan’s work stated. In a 2014 article titled “Time to step up: defending basic science and animal behaviour,” Brennan and other authors argued for the continued support of basic scientific research after U.S. politicians and interest groups deemed several “unusual” scientific studies a waste of spending. 

Today, basic science faces a more positive outlook, according to Brennan. “I think the biggest change happened just now with Covid,” she said, explaining that ongoing research on coronaviruses enabled scientists to rapidly develop a vaccine amid the wave of panic caused by the pandemic. “If we hadn’t had that basic science infrastructure we would’ve been really screwed,” she remarked. Brennan went on to explain that this demonstration of the importance of supporting all types of research led Congress to devote more funding to the National Science Foundation. The AAAS’s support of basic science is another reason why Brennan was excited to be elected as a Fellow, she said. “They really are a fantastic organization and I just couldn’t be happier,” she said. 

Brennan remarked that after working for Yale University and the University of Massachusetts Amherst, Mount Holyoke made an ideal home for her research. “It’s really kind of funny,” she said of the harmony between her research and Mount Holyoke’s status as a historically women’s college, “but it’s perfect because my students are really interested.” Brennan runs a robust lab, with thesis and independent study students conducting research on topics such as shark and ratfish genitalia. She added that our current lack of understanding of female genitalia is “damaging in the long term.” 

“It’s exciting to be at the forefront of those questions at a place like Mount Holyoke,” she said. As a Hispanic woman, Brennan also emphasizes the importance of diversity in research. “If we don’t have diversity in science we are not going to ask the right questions,” she said.