1. Sexual Orientation (pg 10)

2. Sexual Orientation (pg 10)
• Sexual orientation refers to an enduring
pattern of emotional, romantic, and/or sexual
attractions to men, women, or both sexes

3. Sexual Orientation (pg 10)
• Sexual orientation refers to an enduring
pattern of emotional, romantic, and/or sexual
attractions to men, women, or both sexes
• Traditionally defined as
heterosexuality, homosexuality, and
bisexuality (with asexuality a possible 4th
category)

4. • Most people experience little or no sense of
choice about their sexual orientation

5. • Most people experience little or no sense of
choice about their sexual orientation
• Efforts to change sexual orientation are
unlikely to be successful

6. • Most people experience little or no sense of
choice about their sexual orientation
• Efforts to change sexual orientation are
unlikely to be successful
• Early childhood experiences, sexual abuse,
parenting, and other life events do not appear
to influence sexual orientation, but they may
alter sexual expression and behavior

7. Kinsey scale
• 0 = completely heterosexual
• 3 = equally attracted to men and women
• 6 = completely homosexual
• Women are more likely than men to fall near
the middle of the scale

8. Biological Causes of Sexual Orientation
1. Genetics
Identical twins are more likely to share a sexual
orientation than fraternal twins, suggesting a
genetic component

9. 2. Prenatal Hormones
Levels of testosterone in the womb may
influence sexual orientation

10. 2. Prenatal Hormones
Levels of testosterone in the womb may
influence sexual orientation
Finger length ratio, which is controlled by
prenatal hormones, is different in lesbians
than in straight women

11. 2. Prenatal Hormones
Levels of testosterone in the womb may
influence sexual orientation
Finger length ratio, which is controlled by
prenatal hormones, is different in lesbians
than in straight women
Birth order: Men with older brothers are more
likely to be gay because of an immune
response from the mother.

12. Research (pg 11)
• Twin studies
• Chromosome linkage studies
• Epigenetics studies
• Birth order
• Brain structure
• Biological differences in gay men and lesbians
• Sexual orientation and evolution (the “gay uncle
hypothesis”)
• A topic of your choice related to sexual
orientation