||This biographical article is written like a résumé. (October 2009)|
Stephen Marc Breedlove (born 1954) is the Barnett Rosenberg professor of Neuroscience at Michigan State University in East Lansing, Michigan. He was born and raised in the Ozarks of southwestern Missouri. After graduating from Central High School (Springfield, Missouri) in 1972, he earned a bachelor's degree in Psychology from Yale University in 1976, and a Ph.D. in Psychology from UCLA in 1982. He was a professor of Psychology at the University of California, Berkeley from 1982 to 2003, moving to Michigan State in 2001. He works in the fields of Behavioral Neuroscience and Neuroendocrinology. He is a member of the Society for Neuroscience and the Society for Behavioral Neuroendocrinology, and a fellow of the Association for Psychological Science (APS) and the Biological Sciences section of the American Association for the Advancement of Science (AAAS).
In numerous papers, he has demonstrated that steroid hormones and sexual behavior affect the developing and adult spinal cord and brain. He also reported that the average digit ratio of lesbians is more masculine than that of straight women, a finding that has been replicated in his and many other labs and which indicates that lesbians, on average, are exposed to more prenatal testosterone than are straight women. This finding joins many others that biological influences, such as prenatal testosterone and fraternal birth order, act before birth to affect the later unfolding of human sexual orientation, which is the theme for the documentary project Whom You Love.
Breedlove along with other neuroscientists researched PTSD being connected to erectile dysfunction. This erectile dysfunction is usually treated by psychotherapy. Breedlove helped to find the receptor that is affected by the PTSD. This was found through a series of stress tests on rats. The receptor is called the gastrin-releasing peptide (GRP) receptor. This receptor is stress-vulnerable and should be targeted in treatment.
Breedlove also researched how GRP in the lumbar spinal cord could be stimulated for the purpose of curing erectile dysfunction. It was found that the female rats and the male rats with erectile dysfunction had the same amount of GRP. Once the GRP was stimulated in the male rats, androgen receptors worked, and erectile dysfunction was cured. During the experiment, simple erections, dorsal ﬂips of the penis and cup-like ﬂaring erections of the distal glans were measured in the rats before and after probe stimulation.
Breedlove did research on the sex differences in animals in order to understand the sex differences in humans. It was found in rats that the males had more cell numbers in the spinal nucleus of the bulbocavernosus (SNB) than the female rats. These motor neurons appear in both male and female rats, but fade with age in the female rats. Testosterone was also found as the key hormone that is responsible for the differences between males and females.
Breedlove researched the sexual preferences of homosexual men. Using homosexual and heterosexual male participants, it was found that the two groups did not vary according to mating desires. Even though homosexual males cannot reproduce, they, like the heterosexual males, prefer to be with a younger partner. This concludes that both groups' partner references were independent of the evolutionary need for reproduction.
- Breedlove, S. Marc (18 March 2009). "Curriculum Vitae" (PDF). Retrieved 31 October 2009.[self-published source?]
- "Cellular/Molecular Neuroscience Faculty". Michigan State University. 2008. Retrieved 31 October 2009.
- "Neuroscientist and Springfield native shares view on sexual orientation".
- "Donald B. Lindsley Prize in Behavioral Neuroscience".
- "Hormones & Behavior Editorial Board".
- "List of APS Fellows".
- "AAAS Members Elected as Fellows".
- Williams TJ, Pepitone ME, Christensen SE, et al. (March 2000). "Finger-length ratios and sexual orientation" (PDF). Nature. 404 (6777): 455–6. doi:10.1038/35006555. PMID 10761903.
- Brown WM, Finn CJ, Cooke BM, Breedlove SM (February 2002). "Differences in finger length ratios between self-identified 'butch' and 'femme' lesbians" (PDF). Archives of Sexual Behavior. 31 (1): 123–7. doi:10.1023/A:1014091420590. PMID 11910785.
- Tortorice JL (2002). Written on the body: butch/femme lesbian gender identity and biological correlates (Ph.D. Dissertation). Rutgers University. OCLC 80234273.
- McFadden D, Shubel E (December 2002). "Relative lengths of fingers and toes in human males and females". Hormones and Behavior. 42 (4): 492–500. doi:10.1006/hbeh.2002.1833. PMID 12488115.
- Hall LS, Love CT (February 2003). "Finger-length ratios in female monozygotic twins discordant for sexual orientation". Archives of Sexual Behavior. 32 (1): 23–8. doi:10.1023/A:1021837211630. PMID 12597269.
- Rahman Q, Wilson GD (April 2003). "Sexual orientation and the 2nd to 4th finger length ratio: evidence for organising effects of sex hormones or developmental instability?". Psychoneuroendocrinology. 28 (3): 288–303. doi:10.1016/S0306-4530(02)00022-7. PMID 12573297.
- Csathó A, Osváth A, Bicsák E, Karádi K, Manning J, Kállai J (February 2003). "Sex role identity related to the ratio of second to fourth digit length in women". Biological Psychology. 62 (2): 147–56. doi:10.1016/S0301-0511(02)00127-8. PMID 12581689.
- Putz, David A.; Gaulin, Steven J. C.; Sporter, Robert J.; McBurney, Donald H. (May 2004). "Sex hormones and finger length: What does 2D:4D indicate?" (PDF). Evolution and Human Behavior. 25 (3): 182–99. doi:10.1016/j.evolhumbehav.2004.03.005.
- Rahman Q (May 2005). "Fluctuating asymmetry, second to fourth finger length ratios and human sexual orientation". Psychoneuroendocrinology. 30 (4): 382–91. doi:10.1016/j.psyneuen.2004.10.006. PMID 15694118.
- Kraemer B, Noll T, Delsignore A, Milos G, Schnyder U, Hepp U (2006). "Finger length ratio (2D:4D) and dimensions of sexual orientation". Neuropsychobiology. 53 (4): 210–4. doi:10.1159/000094730. PMID 16874008.
- Wallien MS, Zucker KJ, Steensma TD, Cohen-Kettenis PT (August 2008). "2D:4D finger-length ratios in children and adults with gender identity disorder". Hormones and Behavior. 54 (3): 450–4. doi:10.1016/j.yhbeh.2008.05.002. PMID 18585715.
- Grimbos T, Dawood K, Burriss RP, Zucker KJ, Puts DA (2010). "Sexual orientation and the second to fourth finger length ratio: a meta-analysis in men and women". Behav Neurosci. 124 (2): 278–287. doi:10.1037/a0018764. PMID 20364887.
- Breedlove, S.M (2010). "Organizational Hypothesis: Instances of the Fingerpost.". Endocrinology. 151 (9): 4116–22. doi:10.1210/en.2010-0041. PMC . PMID 20631003.
- Puts DA, Jordan CL, Breedlove SM (July 2006). "O brother, where art thou? The fraternal birth-order effect on male sexual orientation" (PDF). Proceedings of the National Academy of Sciences of the United States of America. 103 (28): 10531–2. doi:10.1073/pnas.0604102103. PMC . PMID 16815969.
- S. Marc Breedlove (2015). Principles of Psychology. Oxford University Press. ISBN 978-0199329366
- S. Marc Breedlove, and Neil V. Watson (2013). Biological Psychology: An Introduction to Behavioral and Cognitive Neuroscience (7th Ed). Sinauer Associates. ISBN 978-0-87893-927-5
- Neil V. Watson and S. Marc Breedlove(2016). The Mind's Machine: Foundations of Brain and Behavior (2nd Ed). Sinauer Associates. ISBN 978-1-60535-276-3
- Jill B. Becker, S. Marc Breedlove, David Crews and Margaret M. McCarthy (2002). Behavioral Endocrinology, (2nd Ed). MIT Press. ISBN 978-0-262-52321-9
- Sakamoto, H., Matsuda, K., Zuloaga, D. G., Nishiura, N., Takanami, K., Jordan, C. L., & ... Kawata, M. (2009). Stress Affects a Gastrin-Releasing Peptide System in the Spinal Cord That Mediates Sexual Function: Implications for Psychogenic Erectile Dysfunction. Plos ONE, 4(1), 1-7. doi:10.1371/journal.pone.0004276
- Sakamoto, H., Matsuda, K., Zuloaga, D. G., Hongu, H., Wada, E., Wada, K., & ... Kawata, M. (2008). Sexually dimorphic gastrin releasing peptide system in the spinal cord controls male reproductive functions. Nature Neuroscience, 11(6), 634-636. doi:10.1038/nn.2126
- Morris, J. A., Jordan, C. L., & Breedlove, S. (2004). Sexual differentiation of the vertebrate nervous system. Nature Neuroscience, 7(10), 1034-1039. doi:10.1038/nn1325
- Gobrogge, K. L., Perkins, P. S., Baker, J. H., Balcer, K. D., Marc Breedlove, S. S., & Klump, K. L. (2007). Homosexual Mating Preferences from an Evolutionary Perspective: Sexual Selection Theory Revisited. Archives Of Sexual Behavior, 36(5), 717-723. doi:10.1007/s10508-007-9216-x
- The Breedlove Jordan Lab Lab home page
- Whom You Love documentary project
- PDF files of selected papers
- PubMed listing of scientific papers
- Principles of Psychology Textbook author
- Biological Psychology Textbook co-author
- The Mind's Machine Textbook co-author
- Biological Psychology Links Web page editor
- Behavioral Endocrinology Textbook co-author
- Summer School of Behavioral Neuroendocrinology Co-Founder
- Neuroscience Program at MSU
- The Science of Sexual Orientation (60 Minutes)
- "Marc Breedlove Named MSU's First Rosenberg Chair in Neuroscience" (Press release). Michigan State University. 22 June 2001. Retrieved 31 October 2009.
- Interview on biology of sexual orientation in the Washington Post
- Author profile on Amazon
- Google Scholar site
- Society for Behavioral Neuroendocrinology
- Society for Neuroscience