Betsy
10-17-02, 07:55 PM
In this weeks New Scientist:
(Of course, they don't mention that stopping surgeries would solve assigning the 'wrong gender') *sigh*
Transcribed
New Scientist. 19 October 2002, p 17
(Gender Identity)
It may be your brain not your genitals that decides what sex you
really are
Our brains could be hard-wired to be male or female long before we
begin to
grow tested or ovaries in the womb. This discovery might explain why some
people feel trapped in a body that's the wrong sex, and could also lead to
tests that reveal the 'brain sex' of babies born with ambiguous genitalia.
Till now, the orthodoxy among developmental biologists has been that
embryos
develop ovaries and become female unless a gene called SRY on the Y
Chromosome is switched on. If this gene is active, it makes testes develop
instead. This switch is seen as the key event in determining whether a
baby
is a girl or a boy. Only after the gonads form and flood the body
with the
appropriate hormones, the theory goes, is the sex of our minds and bodies
determined.
But in a study of mice, a team at the University of California, Los
Angeles,
has now found that males and females show differences in the expression of
no fewer than 50 genes well before SRY switches on. "It's the first
discovery of genes differentially expressed in the brain", says Eric
Vilain,
who led the UCLA team. "They may have an impact on the hard-wired
development of the brain in terms of sexual differentiation independent of
gonadal induction."
Vilain is presenting details of seven of the fifty genes to the annual
meeting of the American Society of Human Genetics in Baltimore this week.
Three of these genes are dominant in females and four are dominant in
males
the next step for Vilain and his team will be to show that the genes in
question really do influence brain sexuality - and not just in mice. This
is likely to be a much tougher proposition than merely showing there are
differences in expression.
But if the findings are confirmed, they could one day yield blood
tests that
allow doctors to establish the brain sex of babies born with genitalia
that
share the features of both sexes. At present doctors and parents have to
guess which gender to assign for surgical 'correction'.
Robin Lovell Badge of the National Institute for Medical research in
London,
who discovered the SRY gene, is already looking at mice with a Y
chromosome
lacking the SRY gene, to see if their brains and behaviour are in any way
male despite their lack of testes. "The growing feeling is that there
will
be direct effects on the brain, anatomy, and behaviour due to X or
Y-linked
genes," says Lovell Badge. "It's early days yet, but we're pretty sure
there
are effects on some aspects of aggression and reproductive behaviour
independent of gonadal sex."
(Andy Coghlan)
(Of course, they don't mention that stopping surgeries would solve assigning the 'wrong gender') *sigh*
Transcribed
New Scientist. 19 October 2002, p 17
(Gender Identity)
It may be your brain not your genitals that decides what sex you
really are
Our brains could be hard-wired to be male or female long before we
begin to
grow tested or ovaries in the womb. This discovery might explain why some
people feel trapped in a body that's the wrong sex, and could also lead to
tests that reveal the 'brain sex' of babies born with ambiguous genitalia.
Till now, the orthodoxy among developmental biologists has been that
embryos
develop ovaries and become female unless a gene called SRY on the Y
Chromosome is switched on. If this gene is active, it makes testes develop
instead. This switch is seen as the key event in determining whether a
baby
is a girl or a boy. Only after the gonads form and flood the body
with the
appropriate hormones, the theory goes, is the sex of our minds and bodies
determined.
But in a study of mice, a team at the University of California, Los
Angeles,
has now found that males and females show differences in the expression of
no fewer than 50 genes well before SRY switches on. "It's the first
discovery of genes differentially expressed in the brain", says Eric
Vilain,
who led the UCLA team. "They may have an impact on the hard-wired
development of the brain in terms of sexual differentiation independent of
gonadal induction."
Vilain is presenting details of seven of the fifty genes to the annual
meeting of the American Society of Human Genetics in Baltimore this week.
Three of these genes are dominant in females and four are dominant in
males
the next step for Vilain and his team will be to show that the genes in
question really do influence brain sexuality - and not just in mice. This
is likely to be a much tougher proposition than merely showing there are
differences in expression.
But if the findings are confirmed, they could one day yield blood
tests that
allow doctors to establish the brain sex of babies born with genitalia
that
share the features of both sexes. At present doctors and parents have to
guess which gender to assign for surgical 'correction'.
Robin Lovell Badge of the National Institute for Medical research in
London,
who discovered the SRY gene, is already looking at mice with a Y
chromosome
lacking the SRY gene, to see if their brains and behaviour are in any way
male despite their lack of testes. "The growing feeling is that there
will
be direct effects on the brain, anatomy, and behaviour due to X or
Y-linked
genes," says Lovell Badge. "It's early days yet, but we're pretty sure
there
are effects on some aspects of aggression and reproductive behaviour
independent of gonadal sex."
(Andy Coghlan)