In August 2017, former Google software engineer James Damore wrote a ten-page manifesto claiming that the disparity between men and women working as software engineers could be explained by biology. The now-infamous document (Damore's Twitter bio reads: "Author of the pro-diversity #GoogleMemo ") said that “men and women biologically differ in many ways” and that this is what led to their representation, or lack thereof, in tech fields.

The unspoken assertion is that women don't biologically belong in leading and demanding fields, and that they are supposed to be in more domestic and servitudinal roles. As we enter the 2020s, it’s clear that refuting this idea is still necessary, even though understanding sex differences this way gets the scientific evidence so wrong .

People still believe that men are somehow biologically programmed to be in charge. As Angela Saini wrote in her 2017 book, Inferior: How Science Got Women Wrong and the New Research That’s Rewriting the Story: "Summers may have dared to say it, but how many people haven't thought the same? That there might be an innate essential difference between the sexes that sets us apart?"

“I’m so used to liberals telling conservatives that they’re anti-science,” Erickson said. “But liberals who defend this and say it is not a bad thing are very anti-science. When you look at biology, when you look at the natural world, the roles of a male and a female in society and in other animals, the male typically is the dominant role.”

In May of 2013, when a Pew study found that mothers were the sole or primary source of income in four of ten American households with children, Fox Business held an all-male panel to respond . Fox News contributor Erick Erickson said that women being breadwinners went against the rules of nature.

The idea that men and women’s differences are derived from biology has haunted the past couple of decades, in fact. You may recall, for instance, that in 2005 , Lawrence Summers, the president of Harvard University, similarly announced that there weren't very many women scientists at elite universities due to "issues of intrinsic aptitude."

For a deep dive into the science of gender differences, Saini's book is excellent. For a narrower counterpoint to the notion of a biologically-mandated male-dominated society, here is a “pro-science” example for female-dominance: the spotted hyena. It is one of several species of animals where the females run the show, and while comparing human societies to animals is problematic (more on that later), reflecting on totally matriarchal hyenas can at least remind us that it's not a steadfast rule that males have to be #1.

Erickson doubled down on his position from the Fox panel in a follow-up blog post . “Pro-science liberals seem to think basic nature and biology do not apply to Homo sapiens. Men can behave like women, women can behave like men, they can raise their kids, if they have them, in any way they see fit, and everything will turn out fine in the liberal fantasy world. Except in the real world it does not work out that way.”

Men and women do think there are variations in how they express themselves, their physical abilities, how they parent, and their hobbies and interests, according to a 2017 Pew survey . But when it comes to the reason for those differences, men and women point to a different cause. Most men think—like Damore—that biology explains it, while more women attribute it to societal expectations. To explain differences between men and women in “the things they’re good at in the workplace,” 61 percent of men said it’s because of biology, compared to 35 percent of women who thought so.

Native to several countries in Sub-Saharan Africa, female spotted hyenas are the typical rulers of their societies, which is rare among mammals. They are about 10 percent larger than males, much more aggressive, and socially dominant to adult males that live alongside them; their clans can comprise up to 90 hyenas all together.

“It’s pretty strikingly obvious when you watch these animals interact” that the females are in charge, said Eli Strauss, a behavioral ecologist who works in the lab of Kay Holekamp, a zoologist at Michigan State University who has been observing hyena behavior for nearly 30 years. “You can see that males are displaced from kills, prevented from feeding, and the females will come in and take the food that the males may have killed themselves.”

After reaching adulthood, males will leave their biological families to become the lowest-ranking members of a new hyena clan. The females remain, and inherit the ranks of their mothers. If you’re the female daughter of the highest-ranking hyena in the clan, you’ll get the most to eat, be the most aggressive, and produce the most successful offspring. “In these and many other respects, spotted hyenas appear to violate many of the accepted ‘rules’ of mammalian biology,” Holekamp wrote in 2011, in a travel diary of her research for the New York Times.

Besides increased aggression, female spotted hyenas have another fascinating feature: masculinized genitalia. Their genitals are so similar to male genitalia at first glance that people believed hyenas to be hermaphrodites for centuries.

The spotted hyena doesn't have a conventional vaginal opening. Instead, her clitoris elongates out of her body, creating a pseudo-penis (also called a pseudo-phallus) that can become fully erect and is the same length as the male’s penis. The females urinate, get pregnant, and give birth through their pseudo-penis. Their labia “are folded over and filled with fat and connective tissue to form a structure that looks remarkably like the male’s scrotal sac,” Holekamp wrote. Even when she was examining a hyena close up, she added: “I thought I was palpating real testes.”