In 2005, Larry Summers, then President of Harvard, raised questions about the disparity in the number of men and women in science, offering, as one explanation, genetic differences between males and females. He got a lot of flack for that comment, but also many came to his defense.
Four years later someone asked a panel of scientists, "the Larry Summers" question:
"Does anyone want to explain the genetic difference between men and women which explains why there are more men than women in science?"
Panelist Neil Degrasse Tyson offered to address the question. Here's what he said:
I’ve never been female, but I have been black my whole life, so let me offer some insights from that perspective because there are many similar social issues related to access to equal opportunity that we find in the black community as well as the community of women in a white male dominated society. . .
I’ve known I wanted to do astro-physics since I was nine years old. Since the first visit to the Hayden Planetarium. So I got to see how the world around me reacted to my expression of these ambitions.
All I can say is, the fact that I wanted to be a scientist and astro-physicist was hands down the path of most resistance through the forces of society. Any time I expressed that interest to a teacher, they’d say, “Don’t you want to be an athlete?” I wanted to become something that was outside the paradigm of expectation of the people in power.
So fortunately my depth of interest was so deep, and so fuel enriched, that every one of these curve balls I was thrown and fences that were in front of me, and hills, I just reached for more fuel and kept going. Now here I am, one, I think, of the most visible scientists in the land and I want to look behind me and say where are the others who might have done this, and they’re not there.
And I wonder, how, where is the blood on the tracks, that I happened to survive and others did not, simply because of the forces of society that prevented, at every turn. To the point that I have security following me every time I go through department stores, presuming I’m a thief. I walked out of a store one time and the alarm went off and so they came running to me. I walked through the gate at the same time a white male walked through the gate. And that guy just walked off with the stolen goods, knowing they would stop me and not him. That’s an interesting exploitation. What a scam that was. People should do that more often.
So, my life experience tells me that when you don’t find blacks in the sciences, you don’t find women in the sciences, I know these forces in the world are real and I had to survive them to get where I am today. So before we start talking about genetic differences, you’ve got to come up with a system where there’s equal opportunity. Then we can have that conversation."
Here's the video I transcribed that from. It's cued to that part.
Few people argue that there are no differences between males and females (though I might argue against such a clear-cut dichotomy and for more of a continuum of gender.) Tyson doesn't argue against a genetic difference. He merely says that, as with African-Americans, that there are so many societal factors stacked against women going into science, that we first need to eliminate that bias before we blame the gaps on gender differences.
Studying societal racial and gender bias is a lot more difficult than writing math tests to document differences. Much of society's sexism and racism is invisible. We aren't talking about "No Blacks Allowed" signs Even the people participating may not realize what they are doing as in the cases Tyson cites.
Here's an example of a study of gender bias using identical resumes except half had male and half had female names. Science faculty were randomly given one or the other resume and asked to evaluate the student for a lab position. Not only were the male resumes rated higher, but they were also assigned a higher salary. This was true whether the faculty rater was a male or female.
This link offers more on the invisible factors.
And here's a link that seems to favor the genetic differences, but shows how complicated the topic and studying it is.
These aren't a representative sample of the literature, but they give you a little sense of what's out there.
I tend to side with Tyson, that the cumulative, lifetime effects on an individual is a significant barrier to overcome for all but the most determined and persistent victims of this mostly invisible, but potent, systemic bias.
[An earlier version was posted at What Do I Know?]