How do undifferentiated embryonic gonads develop into testes or ovaries?

In human embryology, the development of undifferentiated embryonic gonads into testes or ovaries is a process driven by genetic and hormonal influences.1

Initially, all human embryos possess neutral, or indifferent, gonads that have the potential to develop into either male or female organs. The genetic sex is determined at fertilization by the sex chromosome complement: XY for males and XX for females.12

• Testes Development: In XY embryos, specific testis-determining genes located on the Y chromosome direct the undifferentiated gonads to develop into testes. Once formed, the testes secrete hormones, such as Müllerian inhibiting hormone, which cause the female-precursor ducts to atrophy, and testosterone, which stimulates the development of the male genital tract.13
• Ovary Development: In the absence of Y-linked masculinizing influences, the embryo follows a female developmental path. The presence of two X chromosomes is necessary for the development of normal ovaries. In this pathway, the Müllerian ducts develop into female reproductive structures, while the male-precursor Wolffian ducts deteriorate.13