Scientists Grow Teeny Tiny Testicles in Laboratory

Good news for bad nuts: scientists have succeeded in growing itty bitty testicle organoids in a lab.

In a press release, Israel's Bar-Ilan University announced that its researchers had successfully grown artificial testes from mice cells in a petri dish, in a development that could be used to help treat human male infertility in the future.

As microscopic close-ups of the organoids show, they clearly have formed the basic structures of testes, including the tubules through which sperm passes and the general oblong outline of the real thing, too.

Though this is not the first time scientists have managed to grow testicles in the lab — it's happened at least once, when American scientists created a testosterone-producing pair using human stem cells in 2015 to help soldiers whose gonads were injured in combat — this latest success could offer a boon in treatment of male infertility.

Despite not being discussed nearly as frequently as female infertility, it's still a huge deal: as a 2015 paper in the Journal of Human Reproductive Sciences explains, as many as two percent of men globally will exhibit "suboptimal sperm" issues, and of the male-female pairs who present with fertility problems, between 40 and 50 percent do so on account of the swimmers.

In an interview with Israel's Haaretz newspaper, Bar-Ilan's Dr. Nitzan Gonen, a fetal sex determination specialist who heads the school's Institute of Nanotechnology and Advanced Materials, expressed a desire to demystify the understandably awkward discussions surrounding testicles, sperm, and male infertility as she and her colleagues work on their research, which was published recently in the International Journal of Biological Sciences.

"Science today recognizes more than 100 genes in which mutations can cause sex reversal, but we think this is only the tip of the iceberg," Gonen said. "And now we arrive at the reason thanks to which I got into this branch of research; we were looking for a cellular system, an in vitro system, in order to study it. There was no biological system for modeling the testicle until that point."

To be clear, scientists haven't yet been able to grow these artificial balls in vitro, the medical terminology for within the body, nor have they managed to get them to produce sperm. All the same, this advancement marks the first time since the pioneering stem cell research in 2015 that such a feat has been achieved.

So, no swimmers yet — but along with other advancements in lab-grown sperm stem cells, it seems only a matter of time before the birds and bees are recreated in labs and in vitro.

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