Early adolescent sex and diminished school attachment: selection or spillovers?

• Author: Sabia, Joseph J.

1. Introduction

   The public policy debate over abstinence-only versus comprehensive sex education has generally focused on the effects of such programs on adolescent sexual behaviors and health outcomes. (1) However, less attention has been paid to whether the effective promotion of abstinence yields human capital-related benefits. This study explores the relationship between early adolescent sexual activity and four measures of school attachment--suspension from school, unexcused absences, affinity for school, and aspirations to attend college.

   There are several theoretical reasons to expect a negative relationship between early adolescent sex and school attachment. First, sexual intercourse may have adverse psychological, hormonal, or physiological effects on teens that impede human capital accumulation. Moreover, unprotected sex may lead to pregnancies or sexually transmitted infections, which may adversely affect school attachment. Second, it may be that causality runs in the opposite direction. Poor academic achievement may cause teens to psychologically compensate for feelings of loss by engaging in sexual activity. Finally, it may be that there is no causal link between teen sex and school attachment, but rather an association driven by unobserved heterogeneity. Those with the lowest unobserved propensity for human capital accumulation may choose to engage in sexual intercourse at early ages. Carefully addressing the endogeneity of sexual activity will be a central empirical challenge of this study.

   Using the National Longitudinal Study of Adolescent Health, I estimate the relationship between teen sexual activity and school attachment. Controlling for a wide set of individual-level and family-level observables, ordinary least squares (OLS) and school fixed effects (SFE) estimates reflect that sexual activity is associated with diminished school attachment for both adolescent males and females. However, after controlling for individual unmeasured heterogeneity via individual fixed effects (IFE) and instrumental variables (IV), the evidence of a causal link is weaker, with modest adverse effects of adolescent sex observed for younger teenagers.

   For adolescents aged 13-15, IV estimates suggest that early sexual activity is associated with a modestly higher likelihood of reporting at least one unexcused absence from school and a diminished aspiration to attend college. Taken together, these findings suggest that any positive educational spillovers associated with delaying first intercourse tend to be modest and concentrated among the youngest teenagers.

2. Literature Review

   There are several theories in the economic, psychological, and sociological literature that explain a relationship between teen sexual activity and school-related outcomes. Standard rational choice theory suggests that an adolescent will choose to engage in sexual intercourse if the expected gains from engaging in sexual intercourse are greater than the expected costs (see, for example, Nye 1979). The economic theory of fertility, outlined by Becker (1980), implies that those with the lowest shadow prices of sex will choose to engage in it. This theory predicts that those who plan to accumulate the least amount of human capital and have the dimmest future economic prospects will be most likely to exit virginity because they have the least to lose from the consequences of engaging in sexual activity at early ages. Hence, those who are suspended from school, skip classes, feel less a part of their school, and have the least aspirations to attend college are most likely to choose to exit virginity. (2) Thus, when estimating the effect of exiting virginity on school-related outcomes, carefully addressing unmeasured heterogeneity is critical in discerning the nature of the sex-schooling relationship.

   While there are strong theoretical reasons to expect that adverse schooling outcomes will impact teens' sexual decisions, there are several plausible theoretical reasons to expect that exiting virginity will cause adverse schooling outcomes. First, losing one's virginity may lead to teen pregnancies or sexually transmitted diseases, which impede schooling. Second, independent of pregnancy effects, there may be physiological or psychological effects of early teen sex that will impact schooling attachment. Entry into sexual activity could lead to concentration problems for teens, with mental resources substituted away from schooling and toward prurient interests. (3) At the same time, early teen sex could cause teens to lose interest in school, altering their taste for education.

   Moreover, the experience of sexual intercourse may serve as an information revelation mechanism. Once an adolescent has engaged in sexual intercourse, new information may be revealed to him that changes his future investment decisions. For example, if the ex post benefits of sex are higher than the ex ante anticipated benefits, adolescents may choose to substitute away from investments in schooling and toward short-run investments in sexual conquests. In this sense, the experience of sexual intercourse may serve as an information revelation mechanism that causes teenagers to update their beliefs about the benefits and costs of future investment decisions.

   Sociologists and psychologists have posited other theories to explain how sex may affect schooling decisions. Some of these theories are more informative than others. For example, problem behavior syndrome theory posits that immersion in problem behaviors, such as early sexual intercourse, causes a change in an adolescent's mindset such that they will want to explore other nonconformist, antisocial behavior (Donovan, Jessor, and Costa 1988; Elliot and Morse 1989; Rosenbaum and Kandel 1990; Peterson, Moore, and Furstenberg 1991; Farrel, Danish, and Howard 1992; McLean and Flanigan 1993; Whitbeck et al. 1993; Allen, Leadbeater, and Aber 1994; Costa et al. 1995; Harvey and Spigner 1995; Capaldi, Crosby, and Stoolmiller 1996; Schvaneveldt et al. 2001). This theory predicts that the change in mindset or peers caused by sexual experiences could cause teenagers to explore activities such as cutting school, reducing focus in class, and engaging in actions that would result in school suspensions. However, immersion theory does not glean any insight into why adolescents choose to immerse themselves in these behaviors in the first place.

   Another psychological theory used to explain changes in behavior caused by the experience of early first intercourse involves depression. A few studies (see, for example, Rector, Johnson, and Noyes 2003) have found that those who are sexually active are more likely to be depressed and to contemplate suicide. If having sex causes teens to become more depressed or to diminish self-esteem, they may find it more difficult to psychologically cope with schooling responsibilities and become less attached to school. However, no recent studies have convincingly shown evidence of a causal relationship between teen sex and depression. (4)

   While there is an extensive empirical literature exploring the impact of teenage childbearing on future human capital accumulation (see, for example, Geronimus and Korenman 1992; Hoffman, Foster, and Furstenberg 1993; Bronars and Grogger 1994; Rosenzweig and Wolpin 1995; Angrist and Evans 1996; Hotz, Mullin, and Sanders 1997; Klepinger, Lundberg, and Plotnick 1999; Hotz, McElroy, and Sanders 2005), there is far less empirical work examining the effect of losing virginity on schooling outcomes.

   The sociology and psychology literature suggests a strong statistical link between teenage entrance into sexual activity and diminished academic achievement, even after controlling for a wide set of individual-level and family-level observables. Several studies have found that teenagers who have sexual intercourse are more likely to have lower academic achievement and lower academic goals (Jessor et al. 1983; Mott and Marsiglio 1985; Billy et al. 1988; Meilman 1993; Brooke et al. 1994; Costa et al. 1995; Schvaneveldt et al. 2001; Rector and Johnson 2005; Sabia, forthcoming). However, in most of these studies, cross-section OLS models are employed, making it difficult to determine whether there is a causal relationship or simply a correlation due to unobserved heterogeneity. One exception is Sabia (forthcoming), who uses fixed effects and IV methods to show that early teen sex may adversely affect junior high school grade point average (GPA) for adolescent males, but not for females.

   This study contributes to the teen sex-human capital literature by carefully examining the sensitivity of the relationship between early sexual activity and school attachment to unobserved heterogeneity. Unlike previous studies in the literature that have relied on cross-section identification strategies, this study presents fixed effects and instrumental variables estimates, which rely on more credible identification assumptions. These methods will permit more appropriate interpretations of the nature of the relationship between adolescent sexual activity and school-related outcomes.

3. Data

   The dataset used for this analysis is the National Longitudinal Study of Adolescent Health (Add Health), a school-based nationally representative survey with information from adolescents, parents, and school administrators. (5) Adolescents were interviewed in consecutive academic years, in 1994-1995 (wave 1) and again in 1995-1996 (wave 2). In each wave, information on sexual activity, schooling, family, personality, peers, health behaviors, attitudes, and neighborhoods was collected. To reduce the likelihood of reporting error on sensitive topics such as sexual experience, adolescents were assured by interviewers that their answers could not be matched with their names by anyone. Moreover, not even the interviewer knew of the responses since questions were answered via a computer given to the adolescent...