The idea of two sexes is simplistic. Biologists now think there is a wider spectrum than that.
Claire Ainsworth 18 February 2015
As a clinical geneticist, Paul James is accustomed to discussing some of the most delicate issues with his patients. But in early 2010, he found himself having a particularly awkward conversation about sex.
A 46-year-old pregnant woman had visited his clinic at the Royal Melbourne Hospital in Australia to hear the results of an amniocentesis test to screen her baby’s chromosomes for abnormalities. The baby was fine — but follow-up tests had revealed something astonishing about the mother. Her body was built of cells from two individuals, probably from twin embryos that had merged in her own mother’s womb. And there was more. One set of cells carried two X chromosomes, the complement that typically makes a person female; the other had an X and a Y. Halfway through her fifth decade and pregnant with her third child, the woman learned for the first time that a large part of her body was chromosomally male. “That’s kind of science-fiction material for someone who just came in for an amniocentesis,” says James.
Sex isn’t chromosomes: the story of a century of misconceptions about X & Y
The influence of the XX/XY model of chromosomal sex has been profound over the last century, but it’s founded on faulty premises and responsible for encouraging reductive, essentialist thinking. While the scientific world has moved on, its popular appeal remains.
By Ian Steadman
When the International Astronomical Union (IAU) reclassified Pluto from planet to dwarf planet in 2006, it did nothing to change the fact of the existence of Pluto. Its status, however, is an innocuous example of how science is not always an objective descriptor of reality, but an interpreter, loaded with the context of previous generations – how the Greek “planetai” and the post-Copernican “planets” were both labels to describe things that moved in the heavens, even if we realised those things weren’t actually that similar to each other on closer inspection over time.
Klinefelter syndrome (KS) is the leading genetic cause of primary hypogonadism and infertility in men.1,2 The clinical phenotype has expanded beyond the original description of infertility, small testes and gynecomastia.3Animal models, epidemiological studies, and clinical research of males with KS throughout the lifespan have allowed us to better characterize the variable phenotype of this condition. This review will provide an overview on what is known of the epidemiology, clinical features, and pathophysiology of KS, followed by a more focused discussion of testicular development and the clinical management of hypogonadism and fertility in men with KS.