Male contraceptive pill prototype stops sperm swimming

Unlike the latest option, however, the method required a month of pre-treatment before full effectiveness, and also a steady recovery period to full fertility over a matter of weeks. This doesn’t allow for the same level of spontaneity provided by existing female contraceptives – and (hopefully) TDI-11861 in the near future.

Immediately active after ingestion, like most over the counter pharmacological options, this drug reportedly causes no hormone deficiency side effects. This is because instead of targeting testosterone, scientists found a way of influencing sperm’s cellular signalling protein called soluble adenylyl cyclase or sAC.

‘The approach described here, to knock out key enzyme in sperm that is critical for sperm movement, is a really novel idea. The fact that it is able to act, and be reversed, so quickly is really quite exciting,’ says Professor Allan Pacey of the University of Sheffield.

A disparate group of researchers is looking at a different pathway to temporarily paralyse sperm by blocking a protein on the surface of cells, suggesting this could be the way forward for male contraception – though, obviously, not for protection against sexually transmitted diseases.

In order to get through logistical red tape, the next vital stage in the enzyme’s development is passing human trials. Given the proof-of-concept study has just been completed, that probably won’t occur in the foreseeable future.