Sexual Differentiation of Behavior in Monkeys: Role of Prenatal Hormones

• Type of Material: Article
• Authors: Kim Wallen, Emory University; Janice M. Hassett, Emory University
• Language: English
• Date: 2009-03
• Publisher: Wiley: 12 months
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2009 The Authors. Journal Compilation © 2009 Blackwell Publishing Ltd
• Final Published Version (URL): http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2826.2009.01832.x/abstract;jsessionid=53FF641F9D4C5F8F0F96CB8F5147A148.f04t04
• Title of Journal or Parent Work: Journal of Neuroendocrinology
• ISSN: 0953-8194
• Volume: 21
• Issue: 4
• Start Page: 421
• End Page: 426
• Grant/Funding Information: National Institute of Mental Health : NIMH
• Research Categories: Psychology, General

Abstract

The theoretical debate over the relative contributions of nature and nurture to sexual differentiation of behavior has increasingly moved towards an interactionist explanation requiring both influences. In practice, however, nature and nurture have often been seen as separable, influencing human clinical sex assignment decisions, sometimes with disastrous consequences. Decisions about sex assignment of children born with intersex conditions have been based almost exclusively on the appearance of the genitals and how other’s reactions to the gender role of the assigned sex affects individual gender socialization. Effects of the social environment and gender expectations in human cultures are ubiquitous, overshadowing potential underlying biological contributions in favor of the more observable social influences. Recent work in nonhuman primates showing behavioral sex differences paralleling human sex differences, including toy preferences, suggests that less easily observed biological factors also influence behavioral sexual differentiation in both monkeys and humans. We review research, including Robert W. Goy’s pioneering work with rhesus monkeys which manipulated prenatal hormones at different gestation times and demonstrated that genital anatomy and specific behaviors are independently sexually differentiated. Such studies demonstrate that for a variety of behaviors, including juvenile mounting and rough play, individuals can have the genitals of one sex but show the behavior more typical of the other sex. We describe another case, infant distress vocalizations, where maternal responsiveness is best accounted for by the mother’s response to the genital appearance of her offspring. Together these studies demonstrate that sexual differentiation arises from complex interactions where anatomical and behavioral biases, produced by hormonal and other biological processes, are shaped by social experience into the behavioral sex differences that distinguish males from females.