Nurture Takes the SpotlightDecoding the environment's role in development and disease Christen Brownlee Identical twin sisters Elizabeth and Eleanor (not their real names) say that when they entered the world on November 19, 1939—Elizabeth first, then Eleanor 8 minutes later—their mother was rather shocked. She'd been expecting just one baby, not two. But that day, she made a vow: The girls would always be treated the same, so that there would be no competition between them. POSTER CHILDREN. Illustrating how epigenetics can control physical traits, the slimmer and browner of these mice, carrying a gene called agouti, were born to...