The more a baby weighs at birth and the higher that child's social
class, the smarter that infant will be as a child and adult. Researchers in
Great Britain studied 10,845 males and females who were born between March 3
and March 9, 1958 in England, Scotland, and Wales. At ages 7, 11, 16, and 33
years, the study participants were given cognitive tests and their educational
achievements were noted. The results: Both improved significantly with
increasing birth weight.
Writing in the British Medical Journal, the researchers said
that the proportion of men with higher educational qualifications increased
from 26 percent in the lowest birth weight group (5.5 pounds or less) to 34
percent in the heaviest birth weight group (8.8 pounds or more). For women,
just 17 percent in the low birth weight group had the highest educational
achievements, compared with 28 percent of those with the heaviest birth
weights.
But social background at birth also played an important role,
especially for math scores. The children born into the highest social class
had significantly higher scores than those born in the lowest social class. In
addition, the association between a child's math score and his or her social
class seemed to strengthen with age, while the association with birth weight
remained similar with age.