Psy137SexDevlopmentBrain

Positive feedback on hypothalamic cells t estrogen

Info icon This preview shows pages 26–29. Sign up to view the full content.

View Full Document Right Arrow Icon
positive feedback on hypothalamic cells T (Estrogen) masculinizes the brain and in the process renders M hypothalamic cells unable to switch to positive feedback
Image of page 26

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Brain Activation to Pheromones AND—pheromone released by M EST—pheromone released by F PET scan (rCBF) Controlled for odor areas Found activation in the hypothalamus (MPA & anterior) Heterosexual M show a response to F pheromone and not to M pheromone Heterosexual F show a response to M pheromone and not to F pheromone Homosexual M show response the the M pheromone and not to the F pheromone Homosexual F were not tested
Image of page 27
Genetic Studies of Homosexuality One of the most frequently cited studies of homosexuality was that of Kallmann (1952) in J Nerv Ment Dis: He reported 100% concordance in identical twins for homosexuality, 12% in fraternal twins Subsequent studies have failed to repeat Kallman's findings. Kallman later himself postulated that this impressive concordance was an artifact due to the fact his sample was largely drawn from mentally ill patients. The largest twin study 56 pairs of identical twins, 54 pairs of fraternal twins, 142 non-twin brothers of twins and 57 pairs of adoptive brothers. They found that the concordance rate of homosexuality for: genetically unrelated adoptive brothers was 11% for non-twin biologic brothers about 9% the rate for fraternal twins was 22% and for identical twins it was 52% Rem: this reflects variability accounted by genetics; Note: would also reflect common environmental factors during development
Image of page 28

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Chromosomal Determination of Sexual Orientation. Male twins that are concordant for homosexuality share a portion of the X chromosome. Genetic determinant of sexual orientation: Has been replicated in one of two additional populations by the same group of investigators. Point to ponder: If homosexuality is a gene, how could the gene survive? Surely it would have disappeared due to homosexuals fathering less children? Role of epi factors or epi genetic markers
Image of page 29
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern