Utah startup claims lab-grown sperm produced embryos, awaits peer review

Paterna Biosciences reports successfully generating functional human sperm from testicular stem cells and creating embryos as proof of concept. The Salt Lake City company isolated spermatogonial stem cells from tissue biopsies and developed them into mature gametes in vitro. Co-founder Alexander Pastuszak claims the lab-grown sperm match naturally produced counterparts morphologically and functionally. **Worth flagging:** peer review and independent verification remain absent, leaving reproducibility and safety questions unresolved.