Could sacrificing a tooth enable some infertile men to father children?

That’s the goal of researchers in Brazil, who suggest that stem cells from human teeth can be coaxed into becoming sperm by injecting them into the testes of mice.

The report is published at

Researcher Irina Kerkis of the Butantan Institute, São Paulo, and her colleagues injected stem cells from the dental pulp of human teeth into the testes of live mice.

The cells seemed to migrate to the tubules where sperm usually mature and differentiate into cells resembling human sperm.

However, the process was inefficient and some of the human cells fused with mouse cells – a problem that would have to be solved before the technique could be used therapeutically.

The cells were also taken from baby teeth, so it is unclear if the approach would work with teeth from adult men.

‘I think we are on the right track, but we need to understand more about the mechanism,’ says Kerkis, whose team presented the results at the meeting of the European Society of Human Reproduction and Embryology in Barcelona, Spain, on 9 July.

Other researchers are sceptical. It takes human sperm several weeks to develop, yet the Brazilian team’s cells seemed to have matured within nine days.

Given that human sperm stem cells have previously failed to mature in mouse testes, it seems unlikely that dental cells would fare better, adds Robin Lovell-Badge of the National Institute for Medical Research in London.