Ultrasonic waves directed at the man's testicles, can stop the production of sperm, announced researchers are developing a new method of contraception.
Experiments conducted on rats have shown that sound waves can be used to reduce the sperm count in men's semen to levels which provide infertility.
In an article published in the edition of Reproductive Biology and Endocrinology, scientists call the ultrasound "promising candidate" in the field of contraception.
However, before this method can be used on humans, need a lot of experimenting, scientists say.
This idea was first suggested as far back as the 1970s, but only now researchers at the University of North Carolina, received a grant for this development from the Bill & Melinda Gates Foundation, set out to practical implementation.
They found that two 15-minute sessions is enough to "substantially reduce" the number of sperm-producing cells and the level of sperm.
greatest efficiency is achieved when the sessions held between two days and ultrasound is passed through the warm salt water.
According to the researchers, men have "subfertile" condition occurs when the sperm count in seminal fluid falls below 15 million per milliliter.
In rats, this level fell below 10 million sperm per milliliter.
who heads the research team Dr. James Tsuruta said: "Further research to determine how long this effect persists and is it safe to use this method many times."
Scientists want to make sure that the effects of ultrasound procedures are reversible, that is, that it is contraception rather than sterilization. In addition, it is necessary to determine whether repeated doses produce a cumulative effect.
"It's a nice idea, but you need to have a lot of work," - commented Dr. Alan Pacey opening, a senior lecturer in andrology at Sheffield University.
In his view, the function of sperm production should recover over time, but when it happens, "sperm can be damaged, and in the future the child may be born with disabilities" .
"The last thing we need to defeat the sperm took a protracted nature," - he said.