The fact that IVF is so popular in the United States could protect the practice to some extent, says Hank Greely, director of the Center for Law and the Biosciences at Stanford University in California. But research using human embryos — which is already restricted or even banned in some states — might be an easier target for anti-abortion advocates, some of whom contend that life begins at conception and that discarding an embryo is akin to killing a child. “From a researcher’s perspective, there’s reason to be worried,” he says.