parental schooling and the household wealth index. For all estimates we consider females and males separately. For all estimates we use Huber (1967)-White (1980) robust standard errors to test levels of significance.

**1) Ever in a union and whether young (under 18 y) at initiation of first union and first parenting (Table 2):** Probit estimates do not yield significant effects of schooling attainment on _whether females or males have ever been in a union_ as of the time of the 2002-4 survey.  When schooling is treated as behaviorally-determined with IV probits, whether or not there is control for height, for females greater schooling attainment is estimated to reduce the probability of ever being married significantly<sup>14</sup> and with point estimates about six times as large as in the simple probits. This pattern suggests that there are unobserved factors (e.g. preferences for independence) that directly reduce the probability of ever being in a union and that are positively correlated with schooling attainment, so that when these factors are ignored in the probit estimates, the estimated impact of schooling attainment is greater algebraically (i.e., less negative) than if there is control for these factors.

Probit estimates suggest significant negative effects of schooling attainment on _whether young (under 18 y) at initiation of first union_ for both females and males, but with the estimated associations about three times as large for females as for males. If schooling attainment is treated as behaviorally-determined with IV estimates, there is no evidence of a significant impact for males. For females, in contrast, there still is a significantly negative impact for the alternative IV probit estimates that suggests an effect about 50% bigger in absolute magnitude than in the simple probits. This suggests that for females the unobserved factors that reduce the probability of ever having been in a union also reduce the probability of being in a union when young and – if not controlled in the estimates – lead to underestimates of the impact of schooling attainment on initiating the first union when under 18 y for females.

None of the estimates suggest a significant impact of schooling attainment on _whether young (under 18 y) at time of first parenting_ for males. For females, however, there is a pattern of significant negative estimates similar to those for whether young at initiation of first union – with the IV probit estimates a third to a half bigger in absolute magnitude than the simple probit estimates (though in this case somewhat more of a suggestion that schooling attainment is partly proxying for parental characteristics in the first three estimates if the correct specification is that parental characteristics have direct effects on the outcome as posited in the fourth set of estimates).

**2) Age at first union and first parenting (Table 3):** For males, the censored OLS regression estimates suggest that the _mean age of first union_ for males increases by 0.17 years for every additional grade of schooling attainment.  But when schooling is treated as behaviorally determined, the estimates for males are not significant.  Therefore it appears that there is some unobserved variable that affects positively both schooling attainment and age of marriage for males (e.g., innate ability, ambition, materialism) that, if  not controlled in the estimates, results in the appearance of a significant impact of schooling attainment on age of first union but that is not significant once schooling is treated as behaviorally-determined. For females, in contrast, the censored OLS estimates suggest a much larger (than for males) significantly positive impact of 0.44 years for every additional grade of schooling attainment that persists in the IV estimates – and perhaps even increases if there is control for height.  Height, however, is significantly non-zero only at the 0.10 level and only in the third set of estimates.  In this case it is negative, which suggests that taller

> 14 We use “significantly” to refer to the 0.05 level of significance unless otherwise noted.

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