The latest issue of Science has an article about the preservation of fertility for rhesus monkeys castrated before puberty. The ultimate goal is fertility preservation for boys whose sperm production is destroyed by cancer treatment before puberty.

In the procedure, they castrated prepubertal monkeys, froze the testicles, and later planted small sections of the testicles under the skin on their backs. The testicle sections grew and eventually produced both sperm and testosterone. Sperm was successfully extracted and used to produce a baby rhesus.

They are still a long way from any experiments with humans, but the work is on-going.

Fayomi AP, et al. (2019). Autologous grafting of cryopreserved prepubertal rhesus testis produces sperm and offspring. Science 363 (issue 6433), 1214–1319.

If scientists will find a way , how to cryopreserve organs without disrupting cells during freezing phase by ice crystals, it would be possible to replant testicles later, after cancer treatment. It also gives men second option, who want to become eunuchs, but regret it later. Or second fertility option for transgender people.

I don't think it's likely to help transgender people with fertility. Transplanting testicular tissue into a trans man risks rejection (forcing him to take nasty anti-rejection drugs for as long as the tissue is there) with no substantial benefit. He'd be much better off just injecting testosterone as usual (very safe) and using donor sperm.

boingboing (imported) wrote: Fri Mar 29, 2019 12:32 pm I don't think it's likely to help transgender people with fertility. Transplanting testicular tissue into a trans man risks rejection (forcing him to take nasty anti-rejection drugs for as long as the tissue is there) with no substantial benefit. He'd be much better off just injecting testosterone as usual (very safe) and using donor sperm.

We are talking about own tissue.

A person doesn't reject their own tissue easily, its a perfect DNA match