Government officials in Brazil, Colombia, Ecuador and El Salvador are advising women to avoid getting pregnant, for fear that the fast-spreading Zika virus may cause severe brain defects in unborn children. One question: how? Read More: All the Way Humans Try to Kill Mosquitos—and Why We’re Still Losing With more than a million people infected with the Zika virus in Brazil and millions more cases expected throughout the Americas, government health ministers say the best way to avoid the worst effects of the virus is for women to stop getting pregnant.