题目内容：
Babies who are breast-fed may be more likely to be successful in life, a new study published Tuesday suggests. The study followed more than 3,000 babies into adulthood in Brazil. The researchers found those who were breast-fed scored slightly higher in intelligence tests in their 30s, stayed in school longer and earned more money than those who were given formula（配方奶粉）.“Breast-feeding not only has short-term benefits, but also breast-feeding has long-term benefits, ” says Bernardo Lessa Horta of the Federal University of Pelotas in Brazil, who led the study being published in The Lancet Global Health.
Doctors have long known that breast-feeding can be good for a baby.s health. This is especially true in poor countries, where water can be contaminated. For instance, a baby given formula in developing countries is 14 times more likely to die in the first six months than one who.s breast-fed. In the U.S., some research has suggested that breast-feeding may raise a baby.s IQ（智商）by a few points. But a recent study with siblings（兄弟姐妹）found little advantage to breast-feeding.
Horta says these previous studies didn.t follow children into adulthood to see if breast-feeding had long-term effects. So Horta analyzed data collected from 3,493 volunteers he and his colleagues have been following since birth. They are now in their 30s. First, the researchers gave the subjects
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