Testis tissue from goats and pigs has been grafted onto the backs of mice and shown to produce normal sperm, capable of fertilising eggs.

It is the first time testis tissue from such distant species has produced mature sperm when grafted in mice. “It might work for primates or even humans,” claims Ina Dobrinski of the University of Pennsylvania, one of the co-authors of the study.

If so, the technique could be used to preserve the reproductive potential of male cancer patients about to undergo therapies that would destroy their ability to make sperm. More here.