In a step toward controlling malaria, transgenic mosquitoes engineered to resist the malaria parasite reproduce more successfully than normal mosquitoes when fed on infected mice. If researchers can get them to breed as well on uninfected blood, which so far they cannot, the insects (recognizable by their green fluorescent eyes) may help reduce the proportion of malaria-carrying mosquitoes in the wild. This week's Proceedings of the National Academy of Sciences USA describes the success.