In this paper, we study the impact of prenatal sex selection on the well‐being of girls by analyzing changes in children’s nutritional status and mortality during the years since the diffusion of prenatal sex determination technologies in India. We further examine various channels through which prenatal sex selection might affect girls’ outcomes. Using repeated cross‐sections from a comprehensive dataset, we show that high sex ratios at birth reflect the practice of sex selective abortion. We then exploit the large regional and time variations in the incidence of prenatal sex selection to analyze whether changes in girls’ outcomes relative to boys within states and over time are associated with changes in sex ratios at birth. We find that an increase in the practice of prenatal sex selection appears to be associated with a reduction in the incidence of malnutrition among girls. The negative association appears to be stronger for girls born in rural households and at higher birth parities. An examination of the various mechanisms linking between prenatal sex selection and children outcomes shows that prenatal sex selection does not lead to a selection of girls into better endowed families. However, we find that girls are more likely to be born in families with weaker son preferences and we find a larger reduction in family size for girls relative to boys. We also find an increase in girls’ breastfeeding duration suggesting an improvement in parental care and treatment. On the other we do not find a decline in excess female child mortality or a reduction in son preference as reported by mothers in states with increasing incidence of prenatal sex selection.