Fertility decline, girls' well-being, and gender gaps in children's well-being in poor countries.

The influences of recent dramatic declines in fertility on girls' and boys' well-being in poorer countries are understudied. In panels of 67-75 poorer countries, using 152-185 Demographic and Health Surveys spanning 1985-2008, we examined how declining total fertility and women's increasing median age at first birth were associated with changes in girls' well-being and gender gaps in children's well-being, as reflected in their survival, nutrition, and access to preventive healthcare. In adjusted random-effects models, these changes in fertility were associated with gains in girls' survival at ages 1-4 years, vaccination coverage at ages 12-23 months, and nutrition at 0-36 months (for women's later first childbearing). Declining total fertility was associated with similar gains for boys and girls with respect to vaccination coverage but intensified gender gaps in mortality at ages 1-4 years and malnutrition at ages 0-36 months, especially in higher-son-preference populations. Later increases in women's median age at first birth-reflecting more equitable gender norms-were associated with declines in these gaps. Promoting equitable investments in children through family planning programs in higher-fertility societies is warranted.