A startup out of Utah, Paterna Biosciences, says it has successfully grown functional human sperm in a lab and used the sperm to make visibly healthy-looking embryos. The technique could eventually help men with certain types of infertility have biological children. The findings have not yet been published in a peer-reviewed journal or independently verified. WIRED is the first to report the advance. The process involves isolating sperm-making stem cells from testicular tissue and coaxing the cells into becoming fully-fledged sperm in a dish. Scientists have been attempting to produce sperm outside the body, known as in vitro spermatogenesis, for almost a century. A Japanese team was the first to produce viable mouse sperm in the lab in 2011, but making human sperm has turned out to be a more difficult task.…