When asked about their careers, many scientists talk about mentors, but few bring up mistaken identity. Not so the Sean Carrolls: a cosmologist at California Institute of Technology, who explores conditions in the universe before the Big Bang, and an HHMI investigator at the University of Wisconsin-Madison, who studies how animals develop and evolve.

Caltech's Sean M. Carroll has had several brushes with fame, courtesy of the muddled monikers. “When I was a postdoc in 1994, there was an issue of Time magazine with a cover story about 50 leaders in America under age 40. As a joke, I said, ‘I must be in there,’ and I was. Sort of.” Inside was his name—tied to the biologist's work. “Clearly they had made a mistake,” he jokes. “They picked the wrong Sean Carroll.”

Years later he was invited to a conference at a villa in the Tuscan hills. “Only after I accepted did the organizer come back, very embarrassed, to tell me I was not the right Sean Carroll.”

Both cosmologists and evolutionary biologists can get dragged into arguments with those who try to explain natural phenomena with supernatural explanations, says HHMI's Carroll. “In the blog or Web world, because we both deal at times with anti-science forces, people have contacted us to get clarification about something the other has said.”

Illustration: Peter Arkle

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