A scientific paper released online Sunday reported the first release into the environment of mosquitoes designed to pass a lethal gene on to their offspring.
That gene would kill them before they reached adulthood.
The goal, says Oxitec, the British company which developed the insects, is to cut the number of mosquitoes carrying deadly diseases, like dengue fever and malaria, without more environmentally harmful toxins.
When the altered males mate, their offspring would die before being mature enough to mate.
The first release took part in the Cayman Islands in 2009. There have also been releases in Malaysia and Brazil.
A larger release last year in the Cayman Islands which brought the target mosquito population down by 80 per cent.
Scientists are worried about the release, because once the bugs are out, they can't be brought back in. They are also concerned that Oxitec is moving too fast without sufficient oversight, and isn't doing enough to keep the public in the loop.
A trial of the mosquitoes could be conducted in the Florida Keys. In 2009, it had its first case of dengue fever in many years.