OvaScience is preoccupied by an enduring mystery in human biology—why eggs fail—and the palpable hope that we can do something about it. On the company’s homepage, a beautiful, smiling woman with red hair tumbling down her shoulders gazes at something off-screen. “A woman’s biology is extraordinary,” the tagline reads. Venture capitalists fueled OvaScience with $40 million soon after it launched in 2011, and it raised more than $200 million after going public a year later.