Jacqui Stewart is a retired academic who lectured in medical genetics. She sent this very helpful explanation of the rare but complex chromosomal variants that can affect sexual development. I have her permission to share it here:
The issue of biological "intersex", as it was then called, was well known in medicine, and I was asked several times in my career to contribute to consultations about such individuals. The foundation to this is that nature is not perfect. There are many pathways in the development of a human being (or any living thing), all of which may be occasionally disrupted. So, most humans have a 23rd pair of chromosomes which are either XX or XY. But in a small number of cases, a wide range of variants occur, for example XXY, XYY or XO (only one X). Some of these variants have physically obvious effects and some don't.
Even if an individual has a standard pair of XX or XY sex chromosomes, "normal" development is not guaranteed. There are a number of genes which act on sexual development, which have non functional mutations. Some are on the sex chromosomes and some are not. So receptors with insensitivity to testosterone will produce female development in a chromosomal XY individual. (A rather crude summary is that the basic pattern of embryonic development is female, and a series of switch genes intervene to produce a male). Even when genetic factors are all "normal", babies are still born with so called congenital anomalies, caused by some environmental factor such as exposure to chemical carcinogens. External genitalia and internal reproductive organs may be seriously disrupted.
All of these factors contribute to a serious ethical problem in neonatal medicine. The situation when I worked 40 years ago was that parents had been expecting a baby boy or a baby girl. The concept of intersex was alien and frightening to most people. Babies without normal genitalia were quickly rejected by parents unless there was immediate medical intervention. These were tragic events, with babies simply being left in hospital and parents refusing to take them home. It was easier and more successful in terms of the surgery and endocrinology available then, to create a female appearance . Accordingly, the parents were told that they had a little girl , with some problems that could be treated. And this was felt to produce better outcomes for the children who were accepted into their families in this way.
In fact, this was an evasion of the truth, which is that nature gives us most humans who are male or female by chromosomes, by genes and by embryonic development, but a small number of human beings who are biologically neither. There is no single biological factor which can define male vs female, because these conditions are the result of a complex developmental process. The possession of a chromosomes, or a gene, or tissue, isn't defining for "biological sex". This continues to present a problem to most societies (but as you note in respect of your lectures to African students, not all) where a strict binary understanding of sex and gender prevails.
Recent discussions of issues around people wanting to change gender seem to have made things a little more elastic. It may be that more open discussion on these topics will make biological DSD / intersex less frightening and challenging. There may be more acceptance of such conditions in themselves. It has certainly been put to me by someone in this position that to force on them female gender from birth was an expression of societal prejudice rather than good medical care.
A good book on this subject is "As Nature Made Him: The Boy Who Was Raised as a Girl" by John Colapinto. In this case, a male was raised as a girl. It didn't work. The guilty party was Dr. John Money. He apparently thought that sex and gender can be easily separated.
Thanks so much. Well written, researched and great learning.
Thank you.
Jacqui Stewart is a retired academic who lectured in medical genetics. She sent this very helpful explanation of the rare but complex chromosomal variants that can affect sexual development. I have her permission to share it here:
The issue of biological "intersex", as it was then called, was well known in medicine, and I was asked several times in my career to contribute to consultations about such individuals. The foundation to this is that nature is not perfect. There are many pathways in the development of a human being (or any living thing), all of which may be occasionally disrupted. So, most humans have a 23rd pair of chromosomes which are either XX or XY. But in a small number of cases, a wide range of variants occur, for example XXY, XYY or XO (only one X). Some of these variants have physically obvious effects and some don't.
Even if an individual has a standard pair of XX or XY sex chromosomes, "normal" development is not guaranteed. There are a number of genes which act on sexual development, which have non functional mutations. Some are on the sex chromosomes and some are not. So receptors with insensitivity to testosterone will produce female development in a chromosomal XY individual. (A rather crude summary is that the basic pattern of embryonic development is female, and a series of switch genes intervene to produce a male). Even when genetic factors are all "normal", babies are still born with so called congenital anomalies, caused by some environmental factor such as exposure to chemical carcinogens. External genitalia and internal reproductive organs may be seriously disrupted.
All of these factors contribute to a serious ethical problem in neonatal medicine. The situation when I worked 40 years ago was that parents had been expecting a baby boy or a baby girl. The concept of intersex was alien and frightening to most people. Babies without normal genitalia were quickly rejected by parents unless there was immediate medical intervention. These were tragic events, with babies simply being left in hospital and parents refusing to take them home. It was easier and more successful in terms of the surgery and endocrinology available then, to create a female appearance . Accordingly, the parents were told that they had a little girl , with some problems that could be treated. And this was felt to produce better outcomes for the children who were accepted into their families in this way.
In fact, this was an evasion of the truth, which is that nature gives us most humans who are male or female by chromosomes, by genes and by embryonic development, but a small number of human beings who are biologically neither. There is no single biological factor which can define male vs female, because these conditions are the result of a complex developmental process. The possession of a chromosomes, or a gene, or tissue, isn't defining for "biological sex". This continues to present a problem to most societies (but as you note in respect of your lectures to African students, not all) where a strict binary understanding of sex and gender prevails.
Recent discussions of issues around people wanting to change gender seem to have made things a little more elastic. It may be that more open discussion on these topics will make biological DSD / intersex less frightening and challenging. There may be more acceptance of such conditions in themselves. It has certainly been put to me by someone in this position that to force on them female gender from birth was an expression of societal prejudice rather than good medical care.
A good book on this subject is "As Nature Made Him: The Boy Who Was Raised as a Girl" by John Colapinto. In this case, a male was raised as a girl. It didn't work. The guilty party was Dr. John Money. He apparently thought that sex and gender can be easily separated.