Sex determination through sexual differentiation a case of intersex disorders

chidiebere (54)in #stemng • 7 years ago (edited)

Sex determination is a complex process that is dependent on genetic, hormonal and environmental factors. Conceptus the product of conception, that is the growing baby inside the womb is sexually indifferent up until the age of 6 weeks when phenotipic sexual differentiation commences. But even before then, it already has a genotypic sex which to a large extent determines the phenotypic actual sex.
There are 3 types of sexes during sexual differentiation and each plays an important role in the individuals final sexual identity. These are;

The Chromosomal/Genetic Sex
The Gonadal Sex
And,
The Phenotypic Sex

wikimedia creative commons

The CHROMOSOMAL SEX
This is the genetic sex and is determined at the time of conception. Thus immediately conception takes place the baby's sex is already genetically coded. Genetic Females posses two X chromosomes [XX] , while Genetic Males possesses an X chromosome and a Y chromosome [XY].

GONADAL SEX
The male gonad is the Testis while the Female gonad is the Ovary. What determines the gonadal sex of the conceptus is the presence or absence of the Y chromosome. If the conceptus has a Y-chromosome i.e a genetic male, a gene called the SRY Sex-determining Region on Y-chromosome gene produces a protein called TDF Testis Determining Factor which forms a Testis from the bipotent sexless primitive gonad i.e primitive gonad which has the ability to form either the ovary or testis If the conceptus doesn't have Y chromosome i.e a genetic female, the Ovary by default is formed from the bipotent sexless gonad.

PHENOTYPIC SEX
This is the physical sex, and consists of the internal and external genitalia. It depends on the hormones produced by the gonads.
Testesterone from the Testis masculinizes the conceptus making it to develop epididymis, sperm duct, seminal vesicles and prostate the male internal genitalia, and the penis scrotum and urethra the male external genitalia
Estrogen from the Ovaries feminizes the comceptus making it to develop the Fallopian tubes, womb, cervix, and upper part of the vagina female internal genitalia, and the lower part of vagina, clitoris, and the labia majora and minora female external genitalia.
Thus the physical sex is dependent on the gonadal sex which in turn is dependent on the genetic sex. Understanding this harmony is very important in understanding the concept of hermaphroditism.

300px-Autosomal_recessive_-_en.svg.png

wikipedia: autosomal recessive inheritance

INTERSEX DISORDERS
These arises when there's a disjunction between the three different types of sex described above, say someone who is genetically male having completely female-appearing external features.
In some cases it manifests externally as a genitalia with both female and male features unlike in the last paragraph where allusion is made to cases where the external features are obviously of a particular sex, which however does not correspond to the genetic and gonadal sex. The term ambiguous genitalia is used to describe these cases with shared external gender features. The terms Intersex Disorder and Hermaphroditis has been replaced by the term Disorders of Sexual Development (DSDs) in describing these anomalies as the two former terminologies are perceived as derogatory. Thus even though applying the term transsexuals to people with these anomalies would technically be right, it is frowned upon.

wikimedia: ambiguous genitalia

EXAMPLES OF DISORDERS OF SEXUAL DEVELIPMENT (DSDs)
DSDs are classified based on the genetic sex of the sufferer, which can be argued to be the true sex of the individual. Based on this, there are Genetic Female (46XX) DSDs and Genetic Male (46XY) DSDs among other types.
For want of space, I will be discussing only this two, and doing so with just an example from each.

GENETIC MALE [46 XY] DSDs Using CAIS (Complete Androgen Insensitivity Syndrome) As An Example In CAIS (otherwise known as Testicular Feminization Syndrome)
There is a genetic cum gonadal male with female external genitalia (vagina, clitoris and labia) and somatic features (well developed breasts, wide hips etc, but without a womb. This occurs because the Testosterone (Androgen) that is meant to masculine the external genitalia is not being responded to by the body due to lack of it's receptors. Thus the individual has the genes of a male, has functional testes, like men,which is producing Testosterone, but the body is unresponsive to the testosterone and therefore cannot become the body of a male masculine.
Estrogen from the mother and his own Adrenal glands thus feminizes his body and he becomes a girl with vagina, clitoris, breasts etc.
See it this way, a man goes to the gym with a key testosterone, and on getting to the gym, he discovers that the lock receptors could no longer be opened by the key. And thus he can no longer go to the gym to train. Instead of him to now develop abs, he is now "emasculated" and becomes "effeminate". People with CAIS are exactly females on the outside, and are usually slim and tall,have long hairs, are beautiful and with drop dead gorgeous shape in most cases. Thus most of them end up as models. They don't have Womb and Fallopian tubes because there testis produces something (MIF) that prevents formation of these structures.
Thus they can neither menstruate nor have children. Also there vagina is usually not as deep as that of normal people.

wikipedia: Androgen Insensitivity Syndrome

GENETIC FEMALE [46 XX] DSDs.
Using The Female Variant Of CAH[ Congenital Adrenal Hyperplasia ] As An Example.
In the Female variant of CAH, there is a genetic cum gonadal female, with a womb, but with an Ambiguous genitalia, that is a genitalia that is somewhere between a female's and a male's.
In some cases it could be so severe that it would be very difficult to decide which it is, whether male or female. There has been cases where phenotypic girls were mistakenly raised as boys.
CAH is caused by hormonal imbalance inside the womb, so to say. The Adrenal glands in both sexes produce little amount of sex hormones, especially Androgen. But in CAH due to an enzyme deficiency, it's functions is exaggerated and it produces extremely large amounts of Androgen(Testosterone).
This, in a genetic female, competes with Estrogen, and a battle between feminization and masculinization ensues. The severity depends on the degree to which the excess androgen is able to mask the feminizing effect of Estrogen.
Thus in very severe cases, the two labia majora may meet in the midline just like a scrotum and the Clitoris will be enlarged looking very much like a penis and may contain a urethra for urination. In less severe cases, the clitoris is just enlarged but with no urethra, and the labia are close together but not fused like a scrotum.
Either way, people with CAH usually experience puberty earlier than normal, and while doing so develop secondary male sexual characters like deepening of the voice, growing of beards and developing of male pattern of pubic hair. Also they may have acne. They usually have a problem with fertility as the hormonal imbalance messes up with their menstrual cycle and their ability to ovulate. Just 3 days ago, I saw a case of Ambiguous genitalia in a 8weeks old child with Multiple congenital anomalies including Duodenal Atresia and Congenital Hip Abduction. So these things are not fiction but real,even though not so common.

Human_karyotype_(259_34)_Karyotype_Human_46,XX_(woman).jpg

wikipedia: Human karyotype 46XX

GENDER ASSIGNMENT
This is the process of assigning a gender to an intersex individual, i.e deciding a sex for them.
It involves corrective surgeries and relevant hormone replacement therapy.
Fertility issues should be considered and the sexual role into which the individual would best fit into should be the gender of choice.
This is better done early in life, before the child becomes aware of him/herself to avoid gender identity crisis. It would be psychologically devastating raising a child as a girl, then half way you tell her, you are no longer a girl; you are now a boy. Some school of thoughts though are of the opinion that an intersex child should be raised as such, and be given the opportunity of deciding his/her sex him/herself. According to them, doing otherwise is child right infringement.

CONCLUSION
The challenges faced by individuals with intersex disorders are enormous, especially in a clime such as ours, and include, but not limited to;

Sexual identity crises.
Social discrimination and stigmatization as people see them as freaks.
Fertility issues.
Psychological problems
Medical illnesses peculiar to the different syndromes.
Cancer of the gonads.
All this involves giving them adequate psychological support and getting the society to accept them.

REFERENCES