As I’ve mentioned before on this blog, one of my English teachers at school would occasionally give us exercises in creative writing inspired by `Only Connect’ – the epigraph of the novel Howard’s End by E.M. Forster. We were given two apparently disconnected things (usually news items), asked to think of a possible connection between them and write an story joining them together. From time to time when trying to think of something to write about I’ve resorted to playing the same game and am going to do it today.
This time, I thought I would connect two of my own recent blog posts, one about the case of female boxer Imane Khelife and the other about about the death of theoretical physicist TD Lee. What could the connection be?
Tsung-Dao Lee’s most famous work – for which he won the 1957 Nobel Prize with was on parity violation, which was detected experimentally by Chien-Shiung Wu in 1956. Parity is a conserved quantity in classical physics (e.g. in electromagnetism and gravity) and it was believed until the mid-20th century that it would be conserved in the quantum theory of nuclear interactions too. Wolfgang Pauli, for example, criticized Hermann Weyl’s suggestion of a two-component weakly interacting massless particle because it implied parity violation.
The experimental proof of parity violation in some weak interactions led to a much deeper understanding of fundamental physics, including the the idea of chiral gauge interactions, and the development of the standard model of particle physics. Parity is violated in some strong interactions too. Our simple-minded view of how things are changed as a result of an exception to a widely-held assumption. That’s how progress happens.
You might think now that I’m going to write about the fact that double-helix structure of DNA is right-handed, i.e. that it exhibits a form of parity violation, but that’s not it. Or only a little bit. You see, not all DNA is right-handed…
What does this have to do with Olympic boxing? Well, much of the furore about about Imane Khelif is about the (unproven) assertion that she has XY chromosome and is therefore male and should not be allowed to box in the women’s competition. A ‘biological’ female would have XX chromosomes.
It is true in the vast majority of cases that men have XY chromosomes and women have XX chromosomes, but if you read any reasonably modern book on human biology, the statement that ‘females have XX chromosomes’ is preceded by a “usually” or “in most cases”. But there exceptions: some women have XY chromosomes and some men have XX chromosomes; there are also individuals who have an extra chromosome and are XXY.
How can a person be said to be female if they have XY chromosomes? Well, that is because there is a very long journey between the information encoded in genetic material and the expression of that information in form and function. That entire process determines whether an athlete may nor not have an advantage over another. In a rare, sensible article about the Imane Khelif case I found this
Alun Williams, professor of sports and exercise genomics at Manchester Metropolitan University, said that when considering if a person had an unfair advantage it was necessary to look at chromosomes, levels of testosterone and other hormones, as well as the body’s response to testosterone.
“That then is a clinical assessment, which is really very invasive,” Williams said. “Simply looking at someone’s sex chromosomes … is incomplete.”
In most cases individuals with XY chromosomes develop “male” characteristics and those with XX chromosomes develop “female” but there are exceptions. For example, there are women – with ovaries, a uterus and no male sex organs – who have XY chromosomes. These are biologically female, even if their karyotype indicates otherwise. There is much more to biology than genetics, just as there is much more to physics than electromagnetism and gravity.
I don’t know whether Imane Khelif has XY chromosomes or not, and frankly I don’t care. The fact is that she was assigned female gender at birth, has been raised as female, and her gender is female as on her passport. She is a woman. I won’t use the phrase biological woman, because it is silly: every human being is biological. Caster Semenya is female too.
You might not care about this case and prefer top stick to the rigid definition that XX=male and XY=female. I don’t think that’s appropriate in sports: chromosomes don’t compete in sports, people do. I’ve also been accused of being ‘unscientific’ for accepting that the exceptions to a rule. On the contrary, I think such exceptions are how our understanding improves, not only in scientific terms but also in our respect for our fellow human beings.
