Story perspectives

Human Stem Cells Grow Testis Tissue, Produce Spermatogonia

7/11/2026

Summary

Story summary

Reproductive biologist Eoin Whelan and developmental biologist Kotaro Sasaki transplanted human stem-cell-derived germ cells into a mouse kidney pouch.
The graft self-organized into tubular structures that resembled testicular tissue.
Six months later the human cells differentiated into spermatogonia but did not reach full maturity.
The study is relevant because about 40 % of male-infertility cases lack known causes, yet ethical concerns about lab-grown gametes for designer babies persist.

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Story summary

Reproductive biologist Eoin Whelan and developmental biologist Kotaro Sasaki transplanted human stem-cell-derived germ cells into a mouse kidney pouch.
The graft self-organized into tubular structures that resembled testicular tissue.
Six months later the human cells differentiated into spermatogonia but did not reach full maturity.
The study is relevant because about 40 % of male-infertility cases lack known causes, yet ethical concerns about lab-grown gametes for designer babies persist.