_“In countries where the female secondary education base is low, the expansion of female secondary education may be the best single policy lever for achieving substantial reductions in fertility.” Subbarao and Raney (1995)._

# 1. Introduction

The past 50 years have seen immense transformations in the educational and the reproductive expectations of young people in the developing world: educational levels are going up everywhere (UNESCO statistics), and fertility trends are downward slopping (early fertility and fertility in general). Numerous studies report strong associations between female education and early fertility behavior: teenage pregnancy, age at first birth, contraception use (see CBASSE (1999) for a review of the literature). This evidence has been used as an argument in favor of targeting educational expenditures towards girls. However, most of these studies are based on correlations between years of education and early fertility behavior, often after controlling for community, peers, household and individual characteristics. Part of the correlation between maternal education and early fertility behavior may hence reflect the influence of unobserved background variables correlated with education (in particular personal fertility preferences).

Yet, empirical works do not support the idea that such a simple causal process operates. This lack of evidence is mainly due to the endogeneity of the two decisions: schooling and fertility timing. While there are reasons to expect that a birth during the teen years will often lead to the termination of schooling (time incompatibility, issues of financial support, absence of daycare facilities, cultural factors), it is unclear whether the causality goes from early pregnancy to low levels of schooling or the other way round (endogeneity of choices). A few methodologies have been tried in order to address the possible reverse causality link between education and teenage fertility: comparison between sisters (Geronimus and Korenman (1992)) or between single and twin births (Grogger and Bronars (1993)) to avoid omitted variable bias; instrumentation of age at first birth by age at menarche (Ribar (1992)); miscarriage as an instrument for teenage mothers (Hotz et al. (2004)). The most conclusive studies have used variation in length of schooling, schooling laws (McCrary and Royer (2006), Leon (2004), Black et al. (2004)) or timing of school construction (Breirova and Duflo (2003), Osili and Long (2007)) and all conclude to a reduction in the probability of teenage childbearing due to an additional year of schooling (in the order of magnitude of a 4% reduction<sup>2</sup> ).

Researchers and policy makers are interested in finding ways of reducing teenage pregnancies for early childbearing has been shown to have potentially adverse consequences on the mother, her child and the society as a whole. Early childbearing has been linked to higher rates of maternal and child morbidity and mortality, lower educational achievements, and lower family income. Larger completed family size is one of the long-term demographic effects of adolescent fertility because the timing of the first birth is usually an indicator of future fertility patterns (CBASSE (1987)).

One way of reducing teenage fertility is to directly improve girls’ knowledge about family planning; another is to give them alternative opportunities via schooling (Dryfoos (1983), Subbarao and Raney (1995)). The majority of programs are of the first kind: they are aimed at enhancing young people’s ability to avoid early childbearing and directly influence the process of

> 2 This has to be related to an average probability of giving birth before age 20 of 17% in the selected countries (US and Norway).

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