Wnt signaling in testis development: Unnecessary or essential?

• Wnt signaling's functions have been summarized in testis development.
• The relationship between Wnt signaling and testicular tumor has been illustrated.
• Recent studies and controversial theories have been summarized exhaustively.
• Wnt factors' functions in testis development were specified in model and table.

Testis development is a fundamental process in sexual development and reproduction. It is under the regulation of multiple factors. Wnt signaling pathway is a classical pathway, which plays an essential role during early development. From a traditional view, Wnt signaling serves as a key regulator of female reproductive system. However, its role in testis development is relatively controversial. This paper reviews Wnt signaling's part in the major events during testis development, including primordial germ cell specification, proliferation and migration, testis determination, spermatogenesis and somatic cell regulation, and summarizes Wnt signaling's impact on testis-related disorders. We evaluate the outcomes of current studies in the field and suggest future research directions.