Sexual differentiation is highly dependent on the fetal hormonal environment, guiding sexual development and establishing the foundation for lifelong reproductive health. This short communication highlights critical windows of sex determination and differentiation, emphasizing the role of steroid sex hormones, alongside other factors, in orchestrating these processes in early life. Growing evidence suggests that endocrine-disrupting chemicals (EDCs) can disrupt these tightly regulated pathways, leading to developmental disturbances that manifest as reproductive disorders at birth or later in life. In males, disrupted androgen signaling during fetal development is linked to hypospadias, cryptorchidism, reduced fertility, and testicular cancer, while in females, EDC exposure may contribute to altered ovarian function, early puberty, polycystic ovary syndrome (PCOS), and infertility. By illustrating how EDCs can interfere with sexual development, this brief review underscores the need for further research and regulatory measures to mitigate their impact on human health.