Two boys study together at a Chicago yeshiva in 2009. Public health officials say this type of close physical contact caused a mumps outbreak to spread throughout several orthodox Jewish communities in and around New York City.
M. Spencer Green/AP
An image of researchers at Oregon Health & Science University removing the nucleus from the mother's cell before it's inserted into the donor's egg cell.
Courtesty of Oregon Health & Science University
Inglewood High School cheerleaders perform in front of the Space Shuttle Endeavour as it is transported through the streets of Inglewood and Los Angeles on October 13.
ROBYN BECK/AFP/Getty Images