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I’ve spoken before about the biases rampant in science, due to the disproportionate influence of straight white men in the field. I gave one example of the effects of gender-biased language in scientific papers. But there’s so much more than one example. In fact, there are so many examples that I keep a personal “infuriation diary” of all the scientific articles I or my colleagues come across that are flawed because of gender and sexual bias (and some plain old human sloppiness.) So I will share the latest entries in my infuriation diary with you.

Men with big balls make bad fathers!

Or so this study concludes. What this group did was recruit fathers of babies who were living and co-parenting with their female partners. They gave the mothers and fathers questionnaires about how much each of them contributed to parenting. They recorded brain activity in the fathers when they looked at pictures of their children. Then they measured testicular volume in the fathers.

The group of scientists found a negative relationship between testicular volume and parenting effort in fathers, which they trumpeted as evidence for Life History Theory, which basically says that men have a trade-off between mating effort (time spent courting women and getting them pregnant) and parenting effort (time spent raising babies.)

Which sounds very scientific and all, but the methods are riddled with holes.

your data have problems

Probably the biggest problem is that there’s a big imbalance in the data. They don’t mention this anywhere in the paper, but if you look at the graphs of parenting contribution, only five out of fifty-five fathers reported that they parented more than the mothers. And out of those five, by eyeballing the graph, I’d guess only one or two are significantly different from equality between the parents. So they had only one or two fathers who really parented more than the mothers. For all we know, men who parent a lot more than their partners have enormous balls. But we’ll never know, because those fathers weren’t included in the study.

Another problem is that the fathers’ and mothers’ questionnaires were checked against each other for reliability – they considered the fathers’ self-reports of parenting effort reliable because their partners’ answers backed them up. The problem here is that there are biases in the way people perceive parenting by men and women. Men’s contribution to domestic labor tends to be overreported in questionnaires, while women’s contribution is not (source). Giving the parents time diaries where they must note what they’re doing all day long are more reliable measures than questionnaires, especially when it comes to reporting men’s contributions.

The third problem, of course, is that they only used men who were raising children with women! I suspect the authors would consider men who co-parent with other men to be categorically different from the men they studied, but if they had a reason to exclude men parenting with other men, they should have specified it in the paper.

Why does the female orgasm exist? Scientists are mystified!

So recently I saw a study that found that female orgasm rate has no effect on the number of children a woman has.

It isn’t that I think these results are surprising. It’s that I’m astonished that anyone still thought that having more babies was some kind of evolutionary reason for female orgasms in the first place. I thought we’d moved on from this idea since the Elizabethan era!

To give some background, the female orgasm first evolved in primates. Monkeys and apes of all sorts have orgasms in both sexes. Researchers are interested in the evolution of the female orgasm because unlike the male orgasm, it’s not directly and obviously related to reproduction. Males obviously can’t reproduce with ejaculating, so it makes sense that that activity would be associated with pleasure. But why, scientists ask, did female primates evolve orgasm?

After seeing this article and its totally unsurprising conclusion, I looked into current hypotheses for the evolution of the female orgasm. One I already saw in the article: that it increases female fertility somehow. No dice. The pair bonding hypothesis posits that the female orgasm promotes pair-bonding with the father so that they’ll stay together and raise kids together. Another is that female orgasm is simply a byproduct of the clitoris and the penis arising from the same basic structures in the fetus. The last, which seems most likely to me, is that the female orgasm is a reward for sex. If sex gives you orgasms, you’ll have more of it, which is good.

Now this study on the female orgasm and fertility concluded that this last hypothesis can’t be true, because they found no correlation between orgasm rate and sexual intercourse. But they defined sexual intercourse as potentially reproductive sex, that is, penis-in-vagina. If they broke down orgasm rate between different types of sex, and broke down the different types of sex the women were having, they might have seen a different picture. Reproductive sex, after all, isn’t the only type of sex that’s relevant to evolution by natural selection. Sex of all types is a powerful pair-bonding activity between individuals of same and different sexes. It promotes social relationships, and social relationships are in turn important to the survival of humans and our relatives.

This is why this study was very frustrating to me; it makes the same mistake as many other studies in this field do, which is to elevate the importance of reproductive sex above all other social behaviors. That bias has a lot of parallels in our everyday lives.

“Humans are dunnocks, not peacocks.”

Unfortunately, there’s no freely accessible version of this article I can share with you, but I recently came across an article on human behavior (source behind paywall) that I found made some good points, but also completely misunderstood its own good points. It was written as a reply to another article that made generalizations about how human sexual behavior fits into broader patterns of sexual behavior in mammals.

peacock and peahen

Hello, ladies.

The text in bold was the title of the article. What does it mean? Well, peacocks and dunnocks are used here as metaphors for two different social/sexual systems. Peafowl are species in which males compete and females choose their favorites to mate with. This system is often called “polygyny,” which I find a misnomer in most cases it’s used, because it implies that males have many female mates, while females are… doing what, exactly? Half of all peahens mate with more than one male, so we could just as well call them “polyandrous.” The author of the article calls the social/sexual system of peafowl MCFC, which stands for “males compete, females choose.” This to me seems more apt. The real difference between peacocks and peahens is not whether they mate with more than one partner, but in the difference within each sex. A few peacocks get to mate with many peahens, while the other peacocks don’t get to mate at all; by contrast, almost all peahens get to mate.


A sexually adventurous songbird.

Dunnocks are small brown birds that live in Europe and Asia. They are very different from peacocks. They can exhibit any of four social/sexual behaviors: monogamy (a pair-bond between a male and a female), polygyny (one male pair-bonded with two females), polyandry (one female pair-bonded with two males), and polygynandry (two males and two females in a merry foursome.) There is no static and universal difference between the sexes as in peafowl; sometimes females compete for males, sometimes males compete for females, and the social/sexual systems they live in all depend on the situation.

The authors of this article argue that humans are much more like dunnocks than peacocks. I agree. Clearly, humans display a broad range of sexual behaviors dependent on context. They also argue that humans can’t be placed in neat categories like MCFC. I agree with that too, and I’d also point out that an important reason scientists have tried to put humans in a peacock-like MCFC framework is because of sexism. But then they go off on tangents about how it makes sense that people studying the evolution of human behavior have focused on MCFC, because the ancestors of humans were probably polygynous.

This is an incoherent argument. We have no real way of knowing what the sexual behavior of our extinct ancestors was like. (Hear that, people who talk about how “cavemen” were “hard-wired” to have sex a certain way?) Our only indicators are sexual dimorphism and phylogeny. Phylogeny is simply comparison between us and our evolutionary relatives. Our closest relatives are chimpanzees and bonobos (source); neither of these species are polygynous. Their sexual systems are best described as all-around promiscuity. They have a lot of sex with a lot of partners, and they don’t have long-term pair bonds. Sexual dimorphism is a measure of size differences between males and females; much larger males generally means the species is polygynous. Humans have some, but not very much, sexual dimorphism, no different from our relatives the bonobos. So there’s really no reason to think our ancestors were polygynous, or that they were any different in their sexual behavior from bonobos and chimpanzees.

You may have noticed that all these articles were in the field of the evolution of human sexual behavior. That’s no accident. I also read plenty of articles about colony collapse disorder in bees and discoveries of planets beyond our solar system, but those don’t generally strike me as gender-biased, whatever their other flaws. It’s hard to be objective about our own species, and those biases really show.