Transcript View as a PowerPoint Slideshow - Building Safe Places for Everyone

Presents
Sexuality and
Variations
Arlene R. Taylor PhD
www.arlenetaylor.org
Brain References
What it Isn’t and What it Is
Arlene R. Taylor PhD
www.arlenetaylor.org
This presentation is not designed to be a
theological or a religious discussion or a
proscriptive ideological ideal
It is designed to share selected
findings on Genetics and
Epigenetics and some of the
discoveries related to human
sexuality and its myriad variations
Nature plus Nurture
Arlene R. Taylor PhD
Realizations Inc
Humans are a combination
• Nature: genetics (genes
and chromosomes / DNA)
• Nurture: epigenetics (environment,
hormones, cellular memory,
gene expression)
Human Are Sexual Beings
Arlene R. Taylor PhD
Realizations Inc
Whatever else human beings are, they are
spiritual, relational, and sexual, whether
or not they engage in sexual activity
The brain is your primary
sex organ―sex begins
and ends in the brain
Your sexual beingness impacts every aspect
of your life, personal and professional―at
home, school, church, work…
Human Genome
Arlene R. Taylor PhD
www.arlenetaylor.org
Your complete set of genetic information
encoded within 23 pairs of chromosomes
in the cell nucleus
(plus cellular memory
in protein strands)
A chromosome is a
single piece of coiled
DNA, a biomolecule that holds the blueprint
for how living organisms are built - 99% of all
DNA (deoxyribonucleic acid) in your body is
found in chromosomes
Genes
Arlene R. Taylor PhD
www.arlenetaylor.org
DNA consists of a 64-letter
(codons) alphabet that
spells out the genetic code
The letters are organized into words and
sentences called genes - a segment of
DNA passed down from parents to child
that confers a trait to the offspring
Humans have 25,000-30,000 genes,
usually in pairs (one from each parent)
New Studies
Arlene R. Taylor PhD
Realizations Inc
For over 40 years we have assumed that DNA
changes affecting the genetic code solely
impact how proteins are made—now we know
that this basic assumption about reading the
human genome missed half of the picture
These new findings highlight that DNA is an
incredibly powerful information storage
device, which nature has fully exploited in
unexpected ways —Dr. John Stamatoyannopoulos
U Washington associate professor of
genome sciences and of medicine
Second Secret Language
Arlene R. Taylor PhD
www.arlenetaylor.org
About 15% of the 64-letter
alphabet (codons) are dual-use
codons (duons) that simultaneously
specify both amino acids and
transcription factor (TF) sequences
This means that many DNA changes that
appear to alter protein sequences may
actually cause disease by disrupting gene
control programs or even both mechanisms
simultaneously —Dr. John Stamatoyannopoulos
Mutations
Arlene R. Taylor PhD
Realizations Inc
A mutation is a change in
the spelling of a DNA sequence
Every person’s DNA contains
mutations that typically are quite harmless
Some mutations, however, are harmful
and may be responsible for triggering
abnormal conditions and specific
diseases (e.g., sickle cell anemia can be
caused by a change in one single gene)
Mitochondria
Arlene R. Taylor PhD
Realizations Inc
Mitochondria are rod-shaped organelles—
power generators (energy factories) inside
the cell—converting oxygen and nutrients
into adenosine
triphosphate (ATP)
ATP is the chemical
energy "currency" of
the cell that powers
the cell's metabolic
processes
Mitochondrial DNA
Arlene R. Taylor PhD
www.arlenetaylor.org
In human cells, 1% of DNA is in the
mitochondria (three dozen
genes), the energy factories
that produce the energyrich molecule known as ATP
or adenosine triphosphate
Scientists are linking mitochondrial DNA
defects with a wide range of age-related
diseases including neurodegenerative
disorders, some forms of heart disease,
diabetes and various cancers
Maternal Mitochondria
Arlene R. Taylor PhD
www.arlenetaylor.org
Unlike chromosomal DNA that
is inherited from both parents,
you get all your mitochondrial
DNA from your mother
Mutations accumulate in mitochondrial DNA
more quickly than in chromosomal DNA, so
it's possible to trace your maternal ancestry
way back beyond any relatives you may
know by name—by tracking the inheritance
of mutations in mitochondrial DNA
Default Setting
Arlene R. Taylor PhD
Realizations Inc
All fetal brains start out
looking very similar
Without conversion, the brain’s
default position will result in an
empathizing (female) brain that
sprouts more connections in the centers
related to communication and processing
of emotion
Chromosomes
Arlene R. Taylor PhD
Pairs 1-22 are
numbered by
appearance
and size—
normally the
same in males
and females
23rd pair = sex
chromosomes
Realizations Inc
Sex Chromosomal Patterns
Arlene R. Taylor PhD
Typical
Empathizing
pattern:
22 pairs
plus XX
www.arlenetaylor.org
Typical
Systemizing
pattern:
22 pairs
plus XY
Default Conversion
Arlene R. Taylor PhD Realizations Inc
Time-lapse photography has
shown that the brain circuits
began to change approximately
six to eight weeks into gestation
The alterations are triggered
based on chromosome patterns and on
available androgens or sex hormones
(especially levels of estrogen and
testosterone)
Conversion, Cont’d
Arlene R. Taylor PhD Realizations Inc
If an XX chromosome pattern:
Developing ovaries alter the levels of
circulating sex hormones (especially
estrogen and some testosterone)
If an XY chromosome pattern:
Developing testicles alter the
of circulating sex hormones (especially
testosterone and some estrogen)
Conversion Impact, Cont’d
Arlene R. Taylor PhD
www.arlenetaylor.org
A healthy “Y” chromosome calls for
the mother’s androgens to give the
developing fetal brain a chemical bath



Brain turns a lavender color temporarily
Maturation of Left hemisphere slows
Development of Right hemisphere
flourishes
Conversion Impact, Cont’d
Arlene R. Taylor PhD





Realizations Inc
Size of 9 / 12 identified areas
is increased
Structure of the inner ear is changed
Cells in communications centers decrease
Cells in sex and aggression centers increase
Size and structure of anterior commissure
and corpus callosum is modified (fewer
axons of smaller diameter)
Templating & Variations
Arlene R. Taylor PhD
Realizations Inc
When everything goes according to
to the perceived schedule, the brain
develops and templates as expected by
family, society, culture, religion, and etc.
Either a primarily Systemizing or
Empathizing brain in which the
brain matches its body housing
Sometime templating mismatches
(variations) occur
Gender Brain Continuum
Arlene R. Taylor PhD
Empathizing
Brain Equated more with
female brains – XX
XO, XXX


Realizations Inc
50-50
Intersex
Brain
Systemizing
Brain Equated more with
male brains – XY
XXY, XXXY, XXXXY
Includes 95% of the population
Checklists of psychological maleness
or femaleness give two scores (no one
is completely empathizing or systemizing)
True Gonadal Intersex
Arlene R. Taylor PhD www.arlenetaylor.org
Person has both ovarian and testicular
tissue; this may be in the same gonad
(an ovotestis) or the person might have
one ovary and one testis
Person may have an XX or XY
chromosomal combination
The external genitals may be ambiguous
or may appear to be female or male
Intersex, Cont’d
Arlene R. Taylor PhD
Realizations Inc
As many as 2% of live births worldwide are
intersex (120 million of six billion people)
―American Journal of Human Biology
Can be divided into several subcategories although causes may
remain undetermined even with
modern advanced diagnostic
techniques
Brain-Body Mismatch
Arlene R. Taylor PhD
www.arlenetaylor.org
There can be a mismatch
between the brain and the body
that houses it – if this causes
enough discomfort, the individual
may want sex-change surgery
There may be more opportunities
for variations in systemizing brains
since the conversion process is so
complicated
Hormonal Variations - 1
Arlene R. Taylor PhD
Realizations Inc
Appearance regardless of chromosomes
AGS
Arlene R. Taylor PhD
www.arlenetaylor.org
Androgenital Syndrome (AGS) –
a condition where an
individual has female
internal organs plus
a form of penis and
scrotum; AGS may be seen in a
chromosomally normal female who was
exposed to a bath of masculinizing
hormones during gestation
—Martin E. P. Seligman, PhD. What You Can
Change…and What You Can’t
Hormonal Variation - 2
Arlene R. Taylor PhD
Realizations Inc
Appearance regardless of chromosomes
AIS
Arlene R. Taylor PhD
www.arlenetaylor.org
Androgen Insensitivity Syndrome (AIS) a condition where an
individual has male
internal organs with
a vagina; may be seen
in a chromosomally
normal male who had
reduced sensitivity to masculinizing
hormones during gestation
—Martin E.P. Seligman, PhD. What You Can
Change…and What You Can’t
Gonadal Intersex or DSD
Arlene R. Taylor PhD
Realizations Inc
Refers to a group of conditions where a
discrepancy exists between external genitals
and internal genitals—typically XY typically
has two testes; XX, two ovaries
The term Hermaphrodite is now DSD
or Disorders of Sex Development
http://www.nlm.nih.gov/medlineplus/ency/article/0016
69.htm
Five Sex Identification Levels
Arlene R. Taylor PhD
www.arlenetaylor.org
1. Genetic sex - chromosome pattern set at
time of conception (e.g., XY, XX, XO, XXY,
XXXY, XXXXY, XY/XO, XXX, … )
2. Gonadal sex - normal testes or ovaries
producing appropriate levels of correct
hormones
3. Genital sex - a normal penis if
male or a normal vagina if female
Five Sex Identification Levels
Arlene R. Taylor PhD
Realizations Inc
4. Brain sex type - systemizing
is stronger in a male brain;
empathizing is stronger in a female brain
5. Sex-typical behaviors - males are more
interested in things and systems; females
in connection and intimacy / emotions
—Dr. Simon Baron-Cohen
The Essential Difference
Sexual Templating #1
Arlene R. Taylor PhD
Realizations Inc
Dr. Gunter Dorner (Germany) - 3 “Centers”
• Sex center that controls characteristics
that are stereotypically male or female
• Mating center
• Gender-role center
Sexual Templating #2
Arlene R. Taylor PhD
Realizations Inc
Dr. Milton Diamond (USA) - 4 “Stages”
• Basic sexual patterning for
passivity or aggressiveness
• Sexual object choice (similar
to Dorner’s mating center)
• Sexual identity (gender mind-set)
• Control over sexual equipment
Sexual Brain Templating
Arlene R. Taylor PhD
www.arlenetaylor.org
Templating appears to involve:
• The 3rd interstitial nuclei of the
anterior hypothalamus (INAH3)

• The bed nucleus of the stria terminalis
(a bundle of nerve fibers that run from
the amygdala on one side of the brain
to the anterior hypothalamus and on to
the amygdala on the other side of the
brain)
Hypothalamus Differences
Arlene R. Taylor PhD
Realizations Inc
The hypothalamus is thought
to be the brain’s sex center

Less than an ounce in weight
and about the size of a cherry, it is larger
in the Systemizing brain than in the
Empathizing brain or in the brains of
homosexuals or transsexuals
—Pease, Barbara and Allan Pease Why Men
Don’t Listen and Women Can’t Read Maps
Neurobiology Transsexual Brain
Arlene R. Taylor PhD
Realizations Inc
Sex differences in size of neurons in bed
nucleus of the stria terminalis: neurons are
usually twice the size in male brains
Post mortem studies of transsexuals (brainbody mismatch) showed these neurons
were the size of what the person believed
they were and not for the gender they were
assigned at birth
―Robert Sapolsky, PhD 2010 Lecture
Phantom Penile Syndrome
Arlene R. Taylor PhD
Realizations Inc
Sixty percent of males who must have
their penis removed due to cancer, report
phantom penile syndrome
Individuals who have their penis
removed due to perceived mismatch
between brain and body, do not show
phantom penile syndrome
―Robert Sapolsky, PhD 2010 Lecture
Misc Brain Differences
Arlene R. Taylor PhD
Realizations Inc
The anterior commissure (one of the three
main bridges between the hemispheres) is
10%-12% larger in the female brain and in
the brains of homosexual males
Homosexual males tend to have
fewer neurons in the 3rd interstitial
nuclei of the anterior hypothalamus
(INAH-3) as compared to the straight male
brain (but more than in the female brain)
—Blum, Deborah Blum, Sex on the Brain
Brain Amygdala Differences
Arlene R. Taylor PhD
Realizations Inc
The amygdala is one of the most well
understood brain regions with regard to
differences between the sexes – larger
male than female amygdalae have been
demonstrated in children ages
7–11 and in adult humans
Involved with emotions and
plays a role in the brain's
reward system
Amygdala Differences #2
Arlene R. Taylor PhD
Realizations Inc
Homosexual men tend to exhibit more
female-like patterns in the amygdala
compared with heterosexual males
Homosexual females tend to
show more male-like patterns
in the amygdala compared
with heterosexual women
Amygdala Differences #3
Arlene R. Taylor PhD
Realizations Inc
Amygdala connections were more
widespread from the left amygdala in
homosexual males, as is also found in
heterosexual females
Amygdala connections were
more widespread from the
right amygdala in homosexual
females, as in heterosexual
males
Religious Tolerance.org
Ontario Consultants on Religious Tolerance
http://www.religioustolerance.org/hom_caus4.htm
Summary of 14 studies that show brain and body
differences between heterosexual and
homosexual individuals (inner ear, finger lengths,
finger ridges, startle reflex, maternal side, etc)
Nobody in science now believes that sexual
orientation is caused by events in adolescence ...
Homosexuality is an early, probably prenatal, and
irreversible preference.
―Author and Geneticist Matt Ridley