FIGURE 9-4 Conceptual model of biological dimension of adolescent sexual behavior.
NOTE: This figure proposes a two-dimensional model of biological influences on the onset of sexual behavior among adolescent males. Increasing levels of testosterone are known to promote sexual behavior in adolescent males through two separate pathways: by increasing secondary sexual characteristics, which are a sign of social maturity, and through libido, which plays a role in sexual initiation. On the other hand, individual variation in cortisol has been related to problem behavior that is known to be related to adolescent sexual behavior. Initiative in sexual behavior is seen here as a form of risk taking. Together sexual opportunity and sexual initiation result in sexual behavior. The role of DHEA/S in sexual behavior is largely unknown. However, it may have direct effects on the disinhibition of social behavior. In addition, DHEA/S antiglucocorticoid actions may reduce the inhibiting effects of cortisol on behavior.
maturation is associated with increases in testosterone that are related to the development of secondary sexual characteristics and the onset of sexual motivation. As such it is related to sexual opportunities.
Risk taking, on the other hand, is associated with socially problematic behavior. As such it may be related to taking advantage of sexual opportunities when such behavior is not normative. Risk taking is related to cortisol, and low cortisol is related to acting on impulse. However, in contrast to testosterone, cortisol levels do not change dramatically at puberty (Walker et al., 2001) and represent a stable individual characteristic preceding puberty.
In the model proposed here, the two dimensions of pubertal maturation and risk taking come together to produce sexual behavior with cortisol modifying the expression of developing sexual impulses produced by increasing testosterone levels, as shown in Figure 9-4.