06/07/2019

Outdated Gender Stereotypes Are Harming Science

16:36 minutes

two white rats with red eyes sit next to each other in the palm of a person's hand
Two young female white rats. Credit: Wikimedia Commons

For half a century, most neuroscience experiments have had one glaring flaw: They’ve ignored female study subjects. The reason? Researchers claimed, for example, that female rats and mice would skew their data, due to hormonal cycling.

Writing in the journal Science, neuroscientist Rebecca Shansky says that view is out of dateand it’s been harming science too. She cites evidence that male mice have as much hormonal variance as female mice, when they’re caged together in the lab. By studying only one sex, she argues, we’re not getting a full picture of how conditions like depression or PTSD might manifest in humans.

Shanksy joins Ira in this segment, along with Radiolab producer and co-host Molly Webster, to talk about the past, present, and future of laboratory research, and whether science can leave these outdated gender stereotypes behind.


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Segment Guests

Molly Webster

Molly Webster is a producer and guest host of WNYC’s Radiolab in New York, New York.

Rebecca Shansky

Rebecca Shansky is a neuroscientist and an associate professor at Northeastern University in Boston, Massachusetts.

Segment Transcript

IRA FLATOW: This is Science Friday. I’m Ira Flatow. 

For the rest of the hour, we’re going to talk about how outdated gender stereotypes about women and men infiltrated decades of experiments on health and fear, and anxiety, and PTSD, because researchers have, in many cases, excluded female mice from those experiments. 

We’ve invited our colleague from WNYC, Molly Webster, here to talk about it. She’s a longtime producer and guest host of Radiolab, was behind the podcast series Gonads last year. All about human development, sex, and gender. 

Molly, welcome back to Science Friday. 

MOLLY WEBSTER: Hey, Ira. 

IRA FLATOW: Is this something you came across in your research for that series? 

MOLLY WEBSTER: Yeah, totally. One of like– I was looking into gender and science. And one of the things I started seeing is we like to think that science is outside of bias infiltrating it, but our feelings about gender affect everything from the way we look down microscopes or the types of questions scientists ask, or even feelings about gender and the emotional tone in which we write a research paper. 

And then last week, there was this article in the journal Science. It was a perspective piece. And it pointed out one of the other ways that gender stereotypes are making their way into lab research. And it’s this idea that female mice are too hormonal. And so they shouldn’t be used in research, because they’ll screw up the data. 

And what they’ve pointed out in this perspective piece is that the male mice actually also have hormones and variability in that hormone. And the piece was a call for researchers to represent the other half of the species in their research. 

And so today, Rebecca Shansky is a neuroscientist and an associate professor at Northeastern University in Boston. She was the author of that science paper, which you can read at ScienceFriday.com/gender. 

Dr. Shansky, welcome to Science Friday. 

REBECCA SHANSKY: Thank you so much for having me. 

MOLLY WEBSTER: So Dr. Shansky, I’m curious what made you write this perspective today. 

REBECCA SHANSKY: So I wrote it today because, actually, a couple of years ago, in 2016, the National Institute of Health, which funds most neuroscience– or most basic science research in the United States, instituted a new policy called considering sex as a biological variable. And what it says is that if you are a scientist and you want money from the NIH, then you have to use animals of both sexes in your research. 

And what that meant for most scientists was that for the first time they were going to have to start using females, because for, basically, since the NIH has been around, most scientists only used males in their research, as you pointed out, because they felt that females were too hormonal. 

And when this policy was announced, there was sort of this cry across the country from basic scientists who basically asked, what are we supposed to do about the hormones now that we have to use females? And it was clearly the most concerning aspect of this new policy for basic scientists. 

And I had, actually, already been studying both males and females because I was really interested in sex differences in a number of different neurobiological processes. And so I had sort of already worked my way through some of these questions. 

And now that I have a little bit more perspective and I was hearing people say, oh, but there’s going to be animals, females, with high estrogen and low estrogen, and it’s going to mess up all my data, and I won’t be able to interpret anything. And I started to think a little bit more deeply about why we consider female animals, female mice, to be so driven by their hormones. Why is this like the one thing that you think sort of makes a female mouse who she is? 

And we don’t really talk that way when we talk about male mice. We say this is the default. This is the standard for how the brain really works. 

And when I was thinking about this idea that we are so concerned with how hormones– and not even so concerned, but so sure that hormones are going to be driving our data points in females, I began to see the parallels between that and the deeply ingrained gender stereotype that women are hormonal, emotional, unstable. There really seemed to be some parallels there. And so that was something I really wanted to explore in this piece. And so that’s why I wrote it now. 

IRA FLATOW: And let me just remind our audience. If you’re a researcher who has had firsthand experience with this, do you use both male and female mice, or flies, or cells in your work? Please give us a call. Our number is 844-724-8255. You can also tweet us @scifri. 

MOLLY WEBSTER: And Dr. Shansky, in your paper you had a quote which made me smile. But it said, “Women, but not men, are still pejoratively described as hormonal or emotional, which curiously neglects the well-documented fact that men also possess hormones and emotions.” It made me giggle. 

And then it also made me think, well, the interesting thing is I do associate, at some level, hormones with female mice and rats. Is that an incorrect assumption? Or is there some nuance that I’m missing? 

REBECCA SHANSKY: So I mean, certainly, female mice and rats do have hormones. And they do fluctuate the way that they do in women. 

The thing I’m trying to point out here is that the hormones for females from a scientific perspective are seen as a problem. They’re seen as a problem, a source of variability of uncertainty in the data, which hasn’t been pointed out as being a problem for male animals, even though across a cohort of male mice, they’re going to have different levels of testosterone. They might have other sources of variability that we don’t necessarily have a guess as to where those sources might come from. 

But when the sort of default was to only study male animals, whatever the sources of variability in your data were across a group of animals, weren’t really seen as a concern. It was just sort of like, oh, that’s a natural variability in your mice, and that’s to be expected, whereas the variability that you get in a cohort of female mice, it’s actually within the same range, and sometimes even lower than the variability you see in a cohort of male mice. And so now it’s like now variability is a problem now that we have to study females. And so it felt like a double standard from a scientific rigor sort of angle. And that was also what I was trying to point out. 

MOLLY WEBSTER: Yeah. I’d want to say that was one of the more surprising parts of your perspective piece, like this idea, which I had never heard before, that hormonal male variability is equal to, if not sometimes greater. Could you talk a little bit more about that? 

REBECCA SHANSKY: Yeah, so one source of hormonal variability in male mice comes from if they are housed together in a cage, which is pretty common. In most scientific vivariums, you’ll have a cage with maybe four or five male mice together because it saves space. But the male mice will usually establish a dominance hierarchy pretty quickly once you put them in the cage together. 

And if you drew blood from each of those mice, the one with the– who turned out to be the alpha male would have up to five times higher testosterone on average compared to the subordinates. And yet it was never a problem from a scientific variability perspective. 

IRA FLATOW: Our number is 844-724-8255. We have a phone call. Let’s go to Tory in Fort Collins. Hi, welcome to Science Friday, Tory. 

TORY: Hi, thank you. 

IRA FLATOW: Go ahead. 

TORY: So I worked in the lab with tamarisk beetles. And during this, the study was about different populations of these beetles and how well they’re controlling invasive plants. And we were looking at how fast they were flying and also, how many eggs the females were laying. 

But for the flying test, we were only testing the males. And I thought that was interesting, because the females had a higher weight because of all the eggs that they have. And we didn’t want that to sort of add another variable to the speed of the different beetle populations. 

But I also think it would have been important to look at that, because, obviously, the females are going to be traveling and spreading the population as well. And I think it would be important to look at. 

IRA FLATOW: It make sense. Thanks. Let me thank you, Tory. 

MOLLY WEBSTER: Is there a– we tend to think, I think, of hormones as very unique. And so they have become this thing in research we don’t want to touch. But Dr. Shansky, is there some sort of– are there other things out there that kind of act similarly– not act similarly– but are like hormones in the sense that they vary between females and males, and yet we’ve learned to live with them? 

REBECCA SHANSKY: Yeah. I mean, certainly, in my field in neuroscience, there are a lot of different things in the brain that just function differently between males and females. And there are– for example, there are some brain regions that are sexually dimorphic. That can come from development. And we don’t necessarily– in some cases, it’s very clear they rule– sorry– govern reproductive function or something like that. So of course, you need things to be different in males and females. 

There are other areas in the brain that we’re just learning about that might work differently in males and females. For example, the dopamine system. There seems to be some important sex differences there as well. 

But a lot of this is just coming out because people are really for the first time really just starting to dig into studying both sexes. 

MOLLY WEBSTER: Hmm. I’m curious where this idea of how hormones affect females– like at what point it entered into lab research. You had an interesting nugget at the top of your piece about the history behind all of this. 

REBECCA SHANSKY: Right. So I started trying to figure out– I was like, OK, when did we start saying women were emotional and hormonal? Where did that come from? 

And I dug a little bit into some gender studies literature and found– so basically, what I learned was that around– a little bit before the turn of the 20th century, the common line about men and women was that women were sort of in an inferior version of men. And that maybe became just a little bit too politically incorrect for the times. 

And so the biologists who were sort of putting forth these theories on gender and biology and sex sort of restructured their narrative. And the goal here was to sort of grant women some sort of uniqueness and say, OK, you have your own qualities. The female psyche is its own thing. It’s not just like a different version of that of males. 

But the qualities that we’re giving you are instability, sensitivity, emotionality, and all of these things, which clearly make you unfit to take on leadership roles in society, essentially. So the goal is to still preserve the patriarchy, to preserve a male-dominated world, but sort of throw this bone to women essentially, where they’re saying, OK, you’re your own person. Yeah. 

IRA FLATOW: I’m Ira Flatow. This is Science Friday from WNYC Studios, talking with Rebecca Shansky, a neuroscientist and associate professor at Northeastern University in Boston, and Molly Webster, producer, and guest host of Radiolab, creator of the podcast series Gonads. 

I have a tweet that came in that sort of is in the same vein from Abbas Jaffary, who writes, “Where do people get the idea that science is free from these stereotypes? STEM is a quintessential example of gender bias in modern society.” 

So why are we so surprised about this, I guess? So what are you saying? Dr. Shansky, what do you say to that? 

REBECCA SHANSKY: Yeah. I mean, I think we shouldn’t be too surprised. Although, as was mentioned earlier, scientists like to– we like to consider ourselves to be unbiased and objective. 

But I think that given the response to this new policy from NIH and even before this policy came out, this was still the running line. If you wanted to study females, you had to figure out how to control for the hormones and whether that meant tracking the hormonal cycle or removing the ovaries altogether so that they didn’t have any circulating hormones. 

And in my graduate work and in my postdoc work, I completely bought into that perspective that the female hormones were something that needed to be dealt with. And things have changed since I started my own lab and have really started to think about, what are we– we’re trying to understand how the brain works. And in a female animal, hormones are a part of how the female brain works. And so why are we trying to change that? We should be working within that structure. 

So yeah, I think it’s not really unsurprising, but I hope that with this piece, it will sort of bring some of these things a little bit more to the surface, and people can think a little bit better how to be unbiased in their research. 

MOLLY WEBSTER: Yeah. It’s interesting. In the perspective, you’re sort of balancing two things, which is saying at some level, there really is no difference in variability of hormone levels between males and females. But then at another level, there actually is. 

Are there cases in which accentuating those differences or– I don’t know– just staring hard at them can actually add into gender stereotypes? 

REBECCA SHANSKY: I mean, there’s always a danger, I guess, when you report research showing sex differences. And I think that the thing that scientists who do study sex differences need to be careful about is the way that you communicate your data to the public and the way that those things are written up, and try to think about where– about the interpretations that can come out of your data. 

So a lot of the– in my field in behavioral neuroscience, a lot of the behavioral tasks that we use have been developed in male animals. And we have kind of standard ways that we interpret what the animal’s behavior is to mean in terms of more sort of like human level psychological constructs. 

And what I think that we’re going to start learning as more and more people start bringing females into these paradigms is that females may be using different strategies to work their way through these paradigms, whether it’s a learning task or a task that’s trying to tap into some sort of emotional dimension. 

So I think that we need to be open-minded about how we interpret some of our data, especially when the metrics were developed on males. 

IRA FLATOW: I’d like to thank my guest this hour Rebecca Shansky, neuroscientist and associate professor at Northeastern University in Boston. 

You can read her paper at ScienceFriday.Com/gender. And of course, my co-pilot Molly Webster, producer and guest host of Radiolab, and creator of the podcast series Gonads. 

Thank you, Molly. And thank you, Dr. Shansky for joining us today. 

MOLLY WEBSTER: Thank you. 

REBECCA SHANSKY: Thank you.

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