a reversible male contraceptive has been been developed by a team of scientists at the All India Institute of Medical Sciences, New Delhi, which could be an alternative to vasectomy. According to S K Guha, who headed the team, a polymer -- styrene maleic anhydride ( sma ) -- is injected into the vas deferens, the pair of tubes through which sperms pass. sma, which is injected as a gel, blocks the tubes preventing the passage of the sperms. Even if some spermatozoa escape the block, they lose their fertilising ability due to the action of the contraceptive.
The scientists describe the new contraceptive as a safe, effective and reversible alternative to vasectomy. N K Lohiya, head of the zoology department of the university of Rajasthan who is collaborating with Guha said that the contraceptive has already been successfully tested on humans in the first phase of the clinical trials. The next two multicentric trials are now in progress. Tests on monkeys after five months of injecting the contraceptive showed complete success, he said.