Good news for gender-balanced family planning advocates worldwide.
Zapping sperm with sound waves has been successfully tested on rats and it’s apparently only a matter of time before it is unleashed on human males, Live Science reports.
Noninvasive ultrasound treatment reduced sperm reserves in rats far below levels normally seen in fertile men, the study researcher James Tsuruta, of the University of North Carolina at Chapel Hill released in a statement. Further studies are needed to determine how long the contraceptive effect lasts, if it is safe to use multiple times and what specific settings work best on humans.
Sperm develops in the testes and goes through multiple intermediate stages. The male birth control method should work on the basis of destroying the earliest stages of sperm development, so the treatment would last a few months.
It’s worked well with rats, but rats are much more fertile than humans, as reported in another Live Science article. Not to mention they don’t have much of a choice here. In the rats, the sperm concentration attained — 3,000 motile sperm or fewer per milliliter — would still allow them to reproduce. In humans that low of a sperm count would be considered infertile. In humans, a low sperm count is defined as anything under 15 million sperm per milliliter. Other permanent sterilization procedures, such as a vasectomy, decrease sperm concentration to 3 million sperm per milliliter.
In other words, they key is to zap, but not to over-zap.