post-ultrasound declines in EFM across SES groups. The magnitudes of the absolute declines are larger in low-SES households where pre-ultrasound rates were higher, but these differences are not statistically significant, and the proportional declines are similar. This is not surprising because even if high-SES households were more affected by the introduction of prenatal sex detection because they showed a greater inclination to substitute sex-selective abortion for fertility-continuation, low-SES households are more “treatable” in any attempt to reduce mortality because it is easier to bring mortality down from initially higher levels.<sup>50</sup> A smaller change in investment can have larger survival impacts in low-SES households as they are more vulnerable to other causes of child mortality, such as infection.

**SES samples by caste.** We also split each SES-subsample by caste.<sup>51</sup> Unlike other dimensions of SES, caste is exogenous in that an individual is born into a caste and remains in it. The caste hierarchy has been preserved by the low prevalence of inter-caste marriages.<sup>52</sup> The upper-castes have historically laid greater emphasis on ritual purity and adherence to religious texts, which often compromises the position of women (Das Gupta et al. (2003), Das Gupta (2010)). In accordance with this, pre-ultrasound excesses in mortality and family size in girl-led families and post-ultrasound declines were, on average, larger in higher caste households. Interacting caste with other indicators of SES shows that at the low-end of the SES distribution, low castes are more gender-equal but at the high-end, low caste behavior is similar to that of high-castes. This is consistent with the process of _Sanskritization_ , wherein lower castes emulate the upper castes in seeking upward mobility (Srinivas (1962)).

**Heterogeneity by religion.** We examine heterogeneity by religion across the two largest religious groups in India, Hindus and Muslims, because they are known to differ in attitudes to abortion. Previous work shows that Muslims, who are more averse to abortion due to religious reasons, are more likely to attain their desired number of sons through son-biased stopping rules, whereas Hindus are more likely to practice sex-selective abortions to achieve the same end (Almond and Edlund (2008), Bhalotra and Cochrane (2010), Bhalotra et al. (2018b)). In line with this, Tables A.17, A.18, and A.19 show that our results on fertility, postnatal health investments, and mortality are driven by Hindus rather than Muslims. In the pre-ultrasound period, Muslim women with a firstborn girl had significantly more children and had significant under-5 EFM relative to those with a firstborn boy as displayed by the coefficients of _Firstgirl * Female_ in Table A.17 and in Panel B of Table A.19. In the post-ultrasound era, when some Hindus switched from fertility continuation or postnatal neglect to sex-selective abortion, Muslims continued, as in the pre-ultrasound 50The one case where group differences in EFM decline are significantly different is in rural relative to urban households. Table 9 shows that absolute declines are significantly larger in rural families but, in fact, the proportional declines are smaller. This is in line with greater prenatal sex-selection in urban areas offsetting the role of higher baseline mortality in rural areas.

> 51We include households of all religions and use the self-reported caste of the household for our analysis while using religion as a control variable. These results are available in Table A.16.

> 52According to the 2005 India Human Development Survey, only 4.4 percent of women were married to a spouse from a different caste.

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