Birth weight predicts scores on the ADHD self-report scale and attitudes towards casual sex in college men: a short-term life history strategy?

Early development can have long-term effects on physiology and behavior. While severe disturbances predictably lead to dysfunction, recent work in humans and animals has led to a growing appreciation for the more subtle ways in which early conditions can modulate behavioral tendencies later in life. Life history theory predicts that early cues signaling a stressful or suboptimal environment might lead an organism to adopt a strategy favoring short-term gains and early reproduction. Fifty college men reported their birth weight, completed the Attention-Deficit/Hyperactivity Disorder (ADHD) Self-Report Scale, and answered a series of questions about their sexual history and attitudes towards short-term sexual encounters. Lower birth weights were associated with higher scores on the ADHD scale (r = -.352; p ≤ .05) and more favorable attitudes towards casual sex (r = -.456; p ≤ 0.001). There was a significant interaction between birth weight and casual sex favorability in predicting number of sexual partners (F1,46 = 4.994; p ≤ .05). This suggests that, although men who are smaller at birth may otherwise be at a disadvantage in reproductive terms, they may offset their reduced fitness by being more willing to engage in casual sex.