Nature or Nurture Revisited
As David assumed his male status, he expressed many of the physical and behavioral traits of typical teenage boys. He was readily accepted by his male peers and engaged in sexual activities with young women. He eventually married and he and his wife enjoyed a loving and fulflling relationship. Unfortunately, David sufered from chronic depression and committed suicide in 2004. The extent to which his childhood experiences contributed to his suicide is unknown.
The case of David Reimer seems to refute the nurture theory; that is, the idea that gender identity is due solely to social efects. However, certain aspects of this case make rejection of the nurture theory premature. For example, David did not begin gender re-assignment until almost two years of age, a period of time that might have been sufficient for establishing a male gender identity. This raises the question of whether gender re-assignment would be successful if initiated at birth. The outcome of this single case does not provide sufficient information for accepting or rejecting either the nature or nurture theory. In spite of over 50 years of research on the sexual differentiation of behavior, there appears to be no consensus on whether a person’s gender identity is shaped by either biological or social variables. Perhaps nature and nurture interact to determine how the sexual self develops.
Evidence for the nature theory of sexual identity is based largely on studies done with laboratory animals (Gorski and Johnson, 1982; Wilson, 1999). There is consensus that the sexual behavior expressed as an adult is the result of exposure to sex hormones during fetal and (or) early postnatal development. Briefy, exposure to testosterone (produced by the testicles) early in life promotes development of the brain in ways that allow male behavior to be expressed as an adult. The absence of testosterone (due to the presence of ovaries instead of testicles) results in a female pattern of behavior. Results of these types of studies are summarized in Table 1.
The extent to which exposure to hormones affects gender identity in humans remains unclear. This is illustrated by two recent studies. Reiner and Gearhart (2004)documented the gender identities of genetically male children who were born without penises, castrated soon after birth, and reared as females. Out of 16 subjects, five were living as females, three had unclear gender identities, and eight were living as males. Of the eight living as males, six underwent male gender re-assignment treatments to obtain masculine physical traits. In a related study, Berenbaum and Bailey (2003) studied the gender identities of 43 girls who were exposed to androgens (hormones similar to and including testosterone) during fetal development. Scores on gender identity interviews for girls exposed to androgens were similar to control girls (not exposed to androgens before birth). Moreover, girls whose exposure to androgens resulted in development of male genitalia were no more likely to express masculine behaviors than control girls.
Task
After completing Part A of the case study and submitting your work, answer the following questions in a form of discussion post. You will be able to read posts from your peers after posting yours.
- How well do the results of studies in humans agree with the studies in rodents that support the nature theory of gender identity? Explain your answer.
- In light of this newer research on gender identity, what advice would you give parents who are considering gender re-assignment of a male infant who lacks a penis, but has functional testicles?
- How would an advocate of the nature theory explain homosexual behavior in men and women?
- How would an advocate of the nurture theory explain homosexual behavior in men and women?
- Design an experiment that would resolve the nature versus nurture controversy. What are some reasons why this experiment hasn’t been done?