Crry exists only in rodents, but two substances--decay accelerating factor (DAF) and membrane cofactor protein (MCP)--serve a like purpose in people. And it is possible that DAF and MCP deficiencies might play a role in miscarriages. Molina's team plans to test this idea next, focusing on women who have suffered multiple miscarriage or have autoimmune diseases such as lupus erythematosus. "Using the mouse studies as a framework," Molina adds, "we can jump to human studies and see whether miscarriages in women also involve complement regulation." If they do, therapies to help certain women carry to term may not be far off.