Week 7 Assigned Reading (Documentary - Why Am I Gay?)

Question 1

Anthony Bogaert’s research features in the documentary. In the original (1996) study by Blanchard & Bogaert, what was the effect (in %) of having older brothers on the chance of a man being gay? What was the purported mechanism? What is the “fraternal birth order effect” and what is the purported mechanism as detailed in Bogaert’s 2018 study? In the interview with Bogaert, what link does he make between the NLGN4Y protein and brain development?

Answer 1

• 1996 Study (Blanchard & Bogaert): Having older brothers increased the chance of being gay by 33%.
• Purported Mechanism (1996): A mother’s immune system responds to male-specific proteins during pregnancy. This response increases with each male pregnancy, possibly affecting the brain development of subsequent sons, contributing to sexual orientation.
• Fraternal Birth Order Effect (2018 Study): Gay men, on average, have more older brothers than heterosexual men. This effect is attributed to the maternal immune response to a male-specific protein (NLGN4Y).
• Purported Mechanism (2018): Bogaert’s 2018 study suggested that maternal antibodies target the NLGN4Y protein, which is crucial for synaptic development in the male fetal brain. This may disrupt sexual orientation development.
• NLGN4Y and Brain Development: The NLGN4Y protein helps form synapses in the brain, and Bogaert hypothesizes that the immune response may interfere with typical male brain development, leading to same-sex attraction.

“More recently, Professor Bogaert has found that the same immunological response might also affect firstborns… [NLGN4Y] helps to create the connections that occur between neurons, the synapses.”

Question 2

In the original (1996) study by Blanchard & Bogaert, what was the effect (in %) of having older brothers on the chance of a man being gay?

Answer 2

1996 Study (Blanchard & Bogaert): Having older brothers increased the chance of being gay by 33%.

Question 3

1996 Study (Blanchard & Bogaert): Having older brothers increased the chance of being gay by 33%.

What was the purported mechanism?

Answer 3

Purported Mechanism (1996): A mother’s immune system responds to male-specific proteins during pregnancy. This response increases with each male pregnancy, possibly affecting the brain development of subsequent sons, contributing to sexual orientation.

Question 4

What is the “fraternal birth order effect”?

Answer 4

Fraternal Birth Order Effect (2018 Study): Gay men, on average, have more older brothers than heterosexual men. This effect is attributed to the maternal immune response to a male-specific protein (NLGN4Y).

Question 5

Fraternal Birth Order Effect (2018 Study): Gay men, on average, have more older brothers than heterosexual men. This effect is attributed to the maternal immune response to a male-specific protein (NLGN4Y).

What is the purported mechanism as detailed in Bogaert’s 2018 study?

Answer 5

Purported Mechanism (2018): Bogaert’s 2018 study suggested that maternal antibodies target the NLGN4Y protein, which is crucial for synaptic development in the male fetal brain. This may disrupt sexual orientation development.

Question 6

In the interview with Bogaert, what link does he make between the NLGN4Y protein and brain development?

Answer 6

NLGN4Y and Brain Development: The NLGN4Y protein helps form synapses in the brain, and Bogaert hypothesises that the immune response may interfere with typical male brain development, leading to same-sex attraction.

Question 7

1996 Study (Blanchard & Bogaert): Having older brothers increased the chance of being gay by __%.

Answer 7

1996 Study (Blanchard & Bogaert): Having older brothers increased the chance of being gay by 33%.

Question 8

_____ Study (_______ & _______): Having older brothers increased the chance of being gay by 33%.

Answer 8

1996 Study (Blanchard & Bogaert): Having older brothers increased the chance of being gay by 33%.

Question 9

A mother’s immune system responds to _____ specific proteins during pregnancy. This response ________ with each male pregnancy, possibly affecting the brain development of subsequent sons, contributing to sexual orientation.

Answer 9

A mother’s immune system responds to male-specific proteins during pregnancy. This response increases with each male pregnancy, possibly affecting the brain development of subsequent sons, contributing to sexual orientation.

Question 10

_______ _____ _____ _____ (____ Study): Gay men, on average, have more older brothers than heterosexual men. This effect is attributed to the maternal immune response to a male-specific protein (NLGN4Y).

Answer 10

Fraternal Birth Order Effect (2018 Study): Gay men, on average, have more older brothers than heterosexual men. This effect is attributed to the maternal immune response to a male-specific protein (NLGN4Y).

Question 11

Fraternal Birth Order Effect (2018 Study): Gay men, on average, have ____ older brothers than heterosexual men. This effect is attributed to the ______ _______ _______ to a male-specific protein (_______).

Answer 11

Fraternal Birth Order Effect (2018 Study): Gay men, on average, have more older brothers than heterosexual men. This effect is attributed to the maternal immune response to a male-specific protein (NLGN4Y).

Question 12

Purported Mechanism (2018): ______ 2018 study suggested that maternal _______ target the ______ protein, which is crucial for _______ development in the male fetal brain. This may disrupt sexual orientation development.

Answer 12

Purported Mechanism (2018): Bogaert’s 2018 study suggested that maternal antibodies target the NLGN4Y protein, which is crucial for synaptic development in the male fetal brain. This may disrupt sexual orientation development.

Question 13

The ______ protein helps form synapses in the brain, and _______ hypothesises that the immune response may interfere with typical male brain development, leading to same-sex attraction.

Answer 13

The NLGN4Y protein helps form synapses in the brain, and Bogaert hypothesises that the immune response may interfere with typical male brain development, leading to same-sex attraction.

Question 14

Regarding genetics, what was the “gay gene” identified by Dean Hamer in 1993? Did the 2019 Ganna study back up the existence of a single “gay gene”? How did the genetic results of participants in the documentary match up with their reported sexual identities (broadly – just say well, moderately, not well). What is the take home message with regards to the contribution of genetics to sexual orientation?

Answer 14

• 1993 Hamer Study (“Gay Gene”): Dean Hamer identified a region of the X chromosome, XQ28, suggesting a genetic link to male homosexuality.
• 2019 Ganna Study: The study found no single “gay gene” but identified five genetic markers statistically associated with same-sex attraction. However, these markers have a small, distributed effect across the genome.
• Results & Sexual Identity: The genetic profiles of participants did not align perfectly with their self-reported sexual identities. In the documentary, most participants showed markers linked to same-sex attraction regardless of their orientation.
• Takeaway on Genetics: Genetics plays a role in sexual orientation, but it is not deterministic. The effect of individual genes is minor, and sexual orientation arises from the interplay of genetics, environment, and possibly other biological factors.

“There is no single gay gene that is linked to same sex behaviour. Instead, like with all human behaviours, there are many genetic effects across the human genome…”

Question 15

Regarding genetics, what was the “gay gene” identified by Dean Hamer in 1993?

Answer 15

1993 Hamer Study (“Gay Gene”): Dean Hamer identified a region of the X chromosome, XQ28, suggesting a genetic link to male homosexuality.

Question 16

Did the 2019 Ganna study back up the existence of a single “gay gene”?

Answer 16

2019 Ganna Study: The study found no single “gay gene” but identified five genetic markers statistically associated with same-sex attraction. However, these markers have a small, distributed effect across the genome.

Question 17

How did the genetic results of participants in the documentary match up with their reported sexual identities (broadly – just say well, moderately, not well).

Answer 17

Results & Sexual Identity: The genetic profiles of participants did not align perfectly with their self-reported sexual identities. In the documentary, most participants showed markers linked to same-sex attraction regardless of their orientation.

Question 18

What is the take home message with regards to the contribution of genetics to sexual orientation?

Answer 18

Takeaway on Genetics: Genetics plays a role in sexual orientation, but it is not deterministic. The effect of individual genes is minor, and sexual orientation arises from the interplay of genetics, environment, and possibly other biological factors.

Question 19

1993 Hamer Study (“Gay Gene”): Dean Hamer identified a region of the __ chromosome, _____, suggesting a genetic link to male homosexuality.

Answer 19

1993 Hamer Study (“Gay Gene”): Dean Hamer identified a region of the X chromosome, XQ28, suggesting a genetic link to male homosexuality.

Question 20

2019 Ganna Study: The study found ___ _____ “gay gene”. It identified ___ genetic markers statistically associated with same-sex attraction. These markers have a ____, distributed effect across the genome.

Answer 20

2019 Ganna Study: The study found no single “gay gene”. It identified five genetic markers statistically associated with same-sex attraction. These markers have a small, distributed effect across the genome.

Question 21

Results & Sexual Identity: The genetic profiles of participants ____ align perfectly with their self-reported sexual identities. In the documentary, ___ participants showed markers linked to same-sex attraction regardless of their orientation.

Answer 21

Results & Sexual Identity: The genetic profiles of participants did not align perfectly with their self-reported sexual identities. In the documentary, most participants showed markers linked to same-sex attraction regardless of their orientation.

Question 22

_______ plays a role in sexual orientation, but it is not deterministic. The effect of individual genes is _____, and sexual orientation arises from the interplay of ______, ______, and possibly other ________ factors.

Answer 22

Genetics plays a role in sexual orientation, but it is not deterministic. The effect of individual genes is minor, and sexual orientation arises from the interplay of genetics, environment, and possibly other biological factors.

Question 23

Briefly describe the results of the study by Morandini (2021) on the fluidity of reported sexuality.

Answer 23

• Key Findings: Sexual orientation can change over time, especially when people are informed that sexuality exists on a spectrum. This flexibility is more prevalent among women.
• Female Fluidity: Heterosexual women exhibit bisexual arousal patterns but often do not identify as bisexual, indicating a potential discrepancy between arousal and self-identification.
• Male Sexuality: Men, in contrast, tend to show more rigid sexual preferences and arousal patterns that align closely with their self-identified orientation.
• Impact of Awareness: Morandini found that when people are introduced to the concept of fluidity, they may begin to report changes in their sexual orientation.
• Generational Differences: Younger people are more open to expressing fluid sexual identities, while older generations tend to adhere to more rigid categories.

“Sexual orientation is becoming more flexible, particularly amongst women… while males are in their boxes, females are a bit more fluid.”

Question 24

_______ found that when people are introduced to the concept of fluidity, they may begin to report changes in their sexual orientation

Answer 24

Morandini found that when people are introduced to the concept of fluidity, they may begin to report changes in their sexual orientation

Question 25

Briefly describe the results of the study by Abe et al. (2014) into brain volume and sexual orientation.

Answer 25

• Study Focus: Abe et al. examined brain volume differences in homosexual and heterosexual men and women.
• Key Finding: The visual cortex of gay men and heterosexual women was thinner compared to heterosexual men.
• Cortical Thickness: The thickness of this area in the brain might correlate with sexual orientation, showing structural differences linked to gender and sexual preferences.
• Link to Gender: These findings suggest that brain anatomy, particularly cortical thickness, may reflect both sexual orientation and gendered processing patterns.
• Neuroscientific Implications: The study supports the idea that certain brain structures are influenced by biological factors tied to sexual orientation.

“One area of the brain, the visual cortex, was thinner in gay men and heterosexual women compared with heterosexual men.”

Question 26

______ et al. examined brain volume differences in homosexual and heterosexual men and women.

Answer 26

Abe et al. examined brain volume differences in homosexual and heterosexual men and women.

Question 27

The _____ cortex of gay men and heterosexual women was ________ compared to heterosexual men.

Answer 27

The visual cortex of gay men and heterosexual women was thinner compared to heterosexual men.

Question 28

Briefly describe the results of the study by Safron et al. (2016) into brain activity and sexual orientation.

Answer 28

• Study Focus: Safron et al. explored brain responses to sexual stimuli in gay and straight men.
• Key Finding: Brain activity was consistent with sexual orientation: homosexual men responded more to male stimuli, while heterosexual men responded more to female stimuli.
• Neurological Responses: The study measured physiological reactions, including eye-tracking and pupil dilation, to determine the sexual interest of participants.
• Reward-Based Response: The study found that gay men showed more brain activity when presented with images of men, indicating arousal and interest in male sexual stimuli.
• Importance of Objective Measurement: By using methods like pupil dilation, researchers could quantify unconscious sexual preferences.

“In 2016 Safron and colleagues found that brain activity was consistent with sexual orientation. Homosexual men would respond to male stimuli while heterosexual men to female stimuli.”

Question 29

_______ et al. explored brain responses to sexual stimuli in gay and straight men and women.

Answer 29

Safron et al. explored brain responses to sexual stimuli in gay and straight men and women.

Question 30

In the original 1996 study by Blanchard & Bogaert, having older brothers increased the chance of a man being gay by ___%.

Answer 30

33%

Question 31

The purported mechanism for the fraternal birth order effect involves the maternal immune system developing antibodies against a male-specific protein called _______, which affects brain development.

Answer 31

NLGN4Y

Question 32

The fraternal birth order effect suggests that gay men have more ___ than heterosexual men.

Answer 32

older brothers

Question 33

Bogaert’s 2018 study suggested that the maternal immune response might disrupt synaptic formation in the male fetal brain by targeting the protein ______.

Answer 33

NLGN4Y

Question 34

One proposed effect of maternal immune response is the disruption of _____/_____development, which may influence sexual orientation.

Answer 34

brain/synaptic

Question 35

In 1993, Dean Hamer identified a region of the X chromosome known as ____, which was initially called the “gay gene.”

Answer 35

XQ28

Question 36

The 2019 Ganna study found ___ genetic markers statistically associated with same-sex attraction, but no single gene responsible for sexual orientation.

Answer 36

five

Question 37

The Ganna study concluded that the contribution of genetics to same-sex sexual behavior is ___, with many genetic effects spread across the genome.

Answer 37

small/minor

Question 38

In the documentary, most participants showed genetic markers linked to same-sex attraction regardless of their _____ _______.

Answer 38

sexual identity

Question 39

The Ganna study emphasizes that ________ alone cannot meaningfully predict someone’s sexual orientation.

Answer 39

genetics

Question 40

Morandini’s 2021 study found that sexual orientation is becoming more ___, especially among women.

Answer 40

fluid

Question 41

Morandini’s 2021 study found while most women show bisexual arousal patterns, only a ________ report being bisexual.

Answer 41

minority

Question 42

Morandini found that when people are introduced to the idea of sexuality as a _______, they may report changes in their orientation.

Answer 42

spectrum

Question 43

Morandini found that men’s sexual preferences tend to be more _____, aligning closely with their stated sexual orientation.

Answer 43

rigid

Question 44

Morandini found that sexual orientation fluidity is more common among _______ generations compared to _______ ones.

Answer 44

younger, older

Question 45

Abe et al. (2014) found that the _____ ____ in gay men and heterosexual women was thinner compared to heterosexual men.

Answer 45

visual cortex

Question 46

Abe et al. (2014) study suggests that the structure of the _____ might correlate with sexual orientation, reflecting brain development differences.

Answer 46

brain

Question 47

Abe et al. (2014) study suggests that cortical thickness in certain brain regions may be influenced by biological factors related to ______ ______.

Answer 47

sexual orientation

Question 48

The visual cortex was found to be ___ in heterosexual men compared to gay men and heterosexual women.

Answer 48

thicker

Question 49

Brain structure differences related to sexual orientation were seen in regions such as the _____ ______.

Answer 49

visual cortex

Question 50

Safron et al. (2016) found that brain activity was consistent with sexual orientation, with homosexual men responding to ___ stimuli.

Answer 50

male

Question 51

The study used measures like ___ dilation and eye-tracking to observe participants’ responses to sexual stimuli.

Answer 51

pupil

Question 52

Heterosexual men responded more strongly to _____ stimuli in Safron et al.’s study.

Answer 52

female

Question 53

Brain activity in response to sexual stimuli can be measured through _________ rewards, such as visual stimuli of nude men or women.

Answer 53

behavioral

Question 54

_____ et al. demonstrated that sexual orientation correlates with brain activity patterns when exposed to stimuli of different genders.

Answer 54

Safron