X|Y & Beyond
Homo sapiens is a sexually dimorphic species; not only as a species but also as individuals. Every human being is originally the product of genetic material from a woman and a man, and male and female anatomy is more similar than different. Human genitalia originally develop the same in both male and female embryos, and all human bodies produce both female and male sex hormones.
Traditionally, gender is seen as a totally unequivocal matter; a person is either 100% one or the other. Human gender is actually much less simple. We can identify at least four distinct components:
physiological: genotype XX or XY \ primary sexual characteristics: genital anatomy \ psychological: secondary sexual characteristics : sexual maturation (BOTH) gender identity: individual's self-perception as male or female
Genetic material is passed on through chromosomes, and every human body cell contains 46 chromosomes arranged in pairs, with the exception of gametes (sex cells). When body cells reproduce, each one divides in two, and each chromosome also divides (mitosis). When the body produces ova and sperm, however, the chromosomes do not divide; instead they are shared between the new cells, so that each contains 23 (meiosis). When a sperm fuses with an ovum it forms a zygote that has 46 chromosomes, half from each parent. This new cell then mitoses in the normal way as the embryo develops.
Of the 46 chromosomes, 44 are arranged in 22 pairs. The final pair are the two sex chromosomes, XX in a woman and XY in a man. When sperm are formed, 50% carry the X chromosome and 50% carry the Y chromosome. The X and Y carry genetic information regarding sexual features, most fundamentally the gender of the embryo.
A human individual is genetically male or female from conception onwards, but anatomically all human beings are fundamentally female. Male characteristics only arise as a result of response to androgens, male sex hormones. Even without the presence of oestrogens (female sex hormones), the embryo would still continue along the path of female development. The developing genitals of male and female human embryos are anatomically identical for the first few months of life. This is why men have nipples. Undifferentiated gametes form, with two sets of ducts (Müllerian ducts and Wollfian ducts); externally a genital protrusion forms with a urethral groove beneath it, flanked by two ridge-like swellings (the labriscrotal swellings).
Primary sexual characteristics arise when gametes
mature and start to produce sex hormones. If the gametes develop into ovaries,
the Wollfian ducts are absorbed and the Müllerian ducts develop into Fallopian
tubes. If the gametes develop into testes the Müllerian ducts are absorbed and
the Wollfian ducts develop into vas deferens and other male genital structures (epidydimis,
seminal vesicles, etc.) In a female embryo, the urethral groove deepens to form
the vulvar opening and the folds become the labia minora. The labriscrotal
swellings form into the labia majora. In a male embryo, the flaps of the groove
fold together to form the urethral tube and shaft of the penis, and the
labriscrotal swellings form the scrotum.
Chromosomal abnormalities: are a common cause of abnormal sexual development, in particular where chromosomes fail to separate during meiosis. For example, if only one of the gametes forming the zygote has a sex chromosome, the individual will only have 45 chromosomes. Having no X chromosome at all would make the zygote unviable; having only one X chromosome is a condition called X0; the individual is female but does not mature sexually. (Did you read that Bill W?)
If one of the two gametes has two X chromosomes instead of one, the resulting zygote will have three X chromosomes, a condition called trisomy X. The individual will be female and may suffer from amenorrhea and a slight degree of mental handicap (incidence 1 in 1000 live births).
If a zygote is formed from a Y chromosome with more than one X (Kleinfelter's syndrome or trisomy XY) the individual will be male but with female secondary sexual characteristics: development of breast tissue, underdeveloped testes, feminine body hair distribution; it may cause slight mental handicap (incidence: 1 in 500 live births).
XYY syndrome, also known as trisomy Y, is where a male has an extra Y chromosome; it does not usually cause sexual abnormalities as such, but may cause a predisposition towards antisocial or violent behaviour, and possible mild mental handicap (incidence: 1 in 700 males).
Hermaphroditism means possessing both male and female anatomical features. True hermaphroditism refers to an individual with one testis and one ovary (or ovotestes may be present); pseudohermaphroditism is a condition in which the gonads are normal but the external genitals are imperfectly developed in men or virilised in women.
Developmental abnormalities: arise from failure of primary sexual characteristics to arise. If a genetically male embryo does not respond to androgens (androgen insensitivity syndrome) the external genitals will fail to develop properly. In mild cases the genitals remain small and childlike, but in more extreme cases the male genitals do not develop at all, but remain in their basic form. When the child is born he will appear to have a vagina, and in most cases the individual's true gender remains unknown and he is raised as a girl. The general shape of the body and face will be female. However, breasts are underdeveloped, the 'vagina' is shallow and he has no ovaries or uterus, retaining vestigial testes within the abdomen.
A similar case is where the penis of a male infant is accidentally destroyed (which has occurred in some cases of circumcision); medics usually advise the parents to raise the child as a girl. This involves surgery and hormone treatment at puberty, but it is regarded as a better option for the individual. Gender identity is fixed within the first two years of life and attempts to alter it usually cause extreme psychological trauma. Life as an infertile woman is considered preferable to life as a man with no penis. In most cases, the child develops fully accepting and adopting the female identity and becoming, for all intents and purposes, a normal heterosexual woman.
Abnormal development of secondary sexual characteristics (the changes that occur in puberty) include androgenital syndrome, in which a girl's body produces more testosterone than normal, leading to the rise of masculine physiological features (virilism).
Similar changes may occur to males and females in later life, when the balance of sex hormone production changes (causing such changes as enlarged male breasts and female facial hair).
The most unusual, and also rarest gender abnormality recorded is a form of human protandry - individuals born anatomically female who then grow up to become male:
After their change, the boys are on average more muscular than their normal brothers. They take on the tough jobs in the local quarry. They marry and lead a normal male sexual life - even though they have not been fertile.
The Batistas are just one of 23 affected families in their village, in which 37 children have changed. In the society of the village - a deeply religious Catholic community - these children's change has been seen as part of God's mysterious ways. They are accepted and allowed to be themselves in a way which couldn't happen in Western society.
In conversation with Dr Gautier, director of the children's hospital on the island, the parents were quite clear about their feelings towards the children. They spoke of their pride in their new sons, of the extra money the children would bring home as boys rather than girls; and they insisted that the children's adjustment to their new gender roles was immediate. Benilda admitted having feelings of sadness and worry; but, supported by a devout community, she came to see the phenomenon as God's will: "If WE made children with our own hands we would make them perfect, beautiful and complete. But God knows what he is doing."
Although girls had been changing into boys since 1930, it was not known outside the district until the first doctor went on holiday there. He published his findings about the children in an obscure Spanish journal, where it lay unnoticed until 1972. Dr Gautier's attention was originally drawn by a patient who had been in his hospital when about eight years old, and whose behaviour had then seemed completely female. And some time later he met that person working in the mountains cutting wood, and his behaviour was as a male. Dr Gautier was so surprised that he and a group of scientists began investigating the change and how it came about.
When scientists put all the family pedigrees together, they began to see the interrelationship between one family and the next. They ended up with an enormous family tree, showing 23 families going back seven generations to one woman - Altagracia Carrasco. She lived in the mid nineteenth century, and she is the commonest ancestor of the affected families. The mutant gene has been passed down from her - but shows only when both parents carry it. How these children develop in the womb has been worked out by the scientists, and it gives a new twist to the story of how male genitals form.
The egg is fertilised by a Y sperm and it first develops to a foetus with normal testes. Perfectly normally, they absorb the female parts, and testosterone preserves the male ducts. But in these children's cases, it doesn't change the external anatomy, because in their bodies the children miss a critical chemical step.
Normal men are able to process cholesterol through to testosterone - and on to a mysterious hormone called dihydrotestosterone. No-one knew what its function was. But because the Caribbean children cannot make it, and because injecting it into them stimulates their genital growth, it is clear now that dihydrotestosterone creates the male external anatomy. The pubertyal surge of testosterone in these children forces up the dihydrotestosterone level and growth that should have happened ten years before, in the mother's womb, takes place at last.
(From The Fight To Be Male from Horizon, At The Frontiers Of Medicine, Ariel Books, BBC 1983)
An individual's self-image of their gender is usually very strongly fixed, especially in adulthood. Most human societies have different roles for different genders, and individuals are conditioned from birth to adopt the appropriate characteristics of behavior for their gender. It is widely believed that these characteristics are 'natural' in the sense that they are somehow in-built and would arise anyway. However, evidence does not suggest this. Ideals of 'masculinity' and 'femininity' are not universal, as we see from anthropological studies:
Among the Manus tribe of New Guinea:
For a year mother and baby are shut up together in the house. For that year
the child still belongs to its mother. But as soon as the child's legs are
strong enough to stand upon and its small arms adept at clutching, the
father begins to take the child from its mother. Now that the child is in no
such need of frequent suckling, he expects his wife to get to work. The plea
that her child needs her would not avail. The father is delighted to play
with the child, to toss it in the air, tickle it beneath its armpits, softly
blow on its bare smooth skin. On the eve of the birth of a new baby, the
child's transfer of dependence to its father is almost complete. While the
mother is occupied with the new baby, the older child stays with its father.
He feeds it, bathes it, plays with it all day. (From Growing up in Guinea,
The Tchambuli tribe of New Guinea: The women go with shaven heads, unadorned, determinedly busy about their affairs. Adult males in Tchambuli are skittish (highly strung and fickle), wary of each other, interested in art, in the theatre, in a thousand petty bits of insult and gossip. The men wear lovely adornments, they do the shopping, they carve and paint and dance. Men whose hair is long enough wear curls, and the others make false curls out of rattan rings. (From Male and Female, Margaret Mead)
Most Western societies are patriarchal, with an extreme dichotomy of power between men and women, but this is a relatively recent phenomenon in human culture. It does not reflect natural tendencies, having more to do with power and social structures. Prior to 5000-8000 BC family structures were undefined; mothers, sisters, brothers, aunts, uncles, etc. all lived together in loose groupings, and the relationships between parent and child were very different to today's norm. Sometimes there was even confusion as to whose child was whose. There was not even a word for 'father' in early Indo-European language, probably because, for centuries, people did not associate sex with reproduction, but simply believed women to be (in some cases divine) creators of life. Elsewhere in the world today there are many matriarchal cultures.
Norms of gender identity in Western culture are usually very strong, as shown in an experiment by Lloyd in 1980. Asking women to play with four six-month old babies (two boys and two girls) they had not met before, they behaved very differently depending upon how the babies were dressed. If the children were dressed in blue it was presumed that they were all boys, and they would be given toy hammers to play with; if they were dressed in pink frilly dresses it was presumed they were all girls, and were given dolls.
The evidence of the Batista children, who started life as girls and then changed into males at the age of twelve, suggests that gender identity is flexible. This is certainly the case among many North American Indian peoples. In a case where male twins wre circumcised, and the penis of one was accidentally destroyed, the child was raised as a girl and psychologically developed as a 'normal' heterosexual woman. The same is true of most individuals born with androgen insensitivity syndrome. It seems that gender identity is purely psychological.
In light of this, transsexualism has traditionally been regarded by the medical profession as a purely psychological condition. Generally, transsexuals are anatomically and physiologically 100% one gender. The deeply-felt conviction the individual holds that they are in some way 'mentally' the opposite gender to their anatomy has always been regarded as a matter for psychiatrists. However, recently researchers have discovered that there are similarities in certain parts of the brain in transsexual men and heterosexual women, suggesting that there may be a neurological basis for transsexualism.
Article Excerpted from L/G Switchboard