BMJ  2005;331 (3 December), doi:10.1136/bmj.331.7528.0-c

Twins have lower IQ in childhood

On average, twins have lower IQ scores at 7 and 9 years old than singleton children in the same family. In a cohort study, Ronalds and colleagues (p 1306) used data on 9832 singletons and 236 twins born in Aberdeen between 1950 and 1956. At age 7, the mean IQ score of twins was 5.3 points lower than that of singletons in the same family, and at age 9, the score was 6.0 points lower. The lower intelligence of twins in childhood may partly be a consequence of the reduced fetal growth and shorter gestations of twins, say the authors.

Credit: ALEX BARTEL/SPL

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

Relevant Article

The cognitive cost of being a twin: evidence from comparisons within families in the Aberdeen children of the 1950s cohort study

Georgina A Ronalds, Bianca L De Stavola, and David A Leon
BMJ 2005 331: 1306. [Abstract] [Full Text] [PDF]