Offspring’s sex composition and childbirth timing in third child transition among Indian mothers born between 1966 and 1985

India faces gender discrimination, leading to skewed sex ratios at birth and influencing family size and the sex composition of already-born offspring. Using the National Family Health Survey-4 (2015-2016), we first apply sequence analysis to investigate the sex composition, mothers’ age at the first child, and childbirth timing for the first two children among Indian mothers born between 1966 and 1985, all of whom are under 30 years old. Second, using logistic regression, we analyze the determinants of the transition to a third child and examine whether the influence of sex composition, combined with timing, has changed over time. We find that education and wealth indices affect mothers’ mean age at first child and the time interval between births. We also observe that women with two daughters are more likely to have a third child, even within younger birth cohorts, despite an overall reduction trend of declining fertility. Through sequence analysis, our study provides unique insights into gender discrimination in India and its implications for fertility across different mothers’ birth cohorts. By identifying the trajectories of sex composition and childbirth timing among previously born offspring, we gain a deeper understanding of the role of male offspring in shaping the likelihood of having a third child while controlling for traditional covariates and mothers’ birth cohorts.