For more than a century, scientists have debated whether intelligence is mostly a product of nature or nurture. Identical ...

Identical twins who were raised apart may have IQ differences similar to those of total strangers, according to new research.

When you’ve just had identical twins, it’s normal to spend a lot of time looking down at their squishy little bodies and analyzing every subtle way they differ from one another. Unlike fraternal twins ...

A new analysis of studies spanning the last century finds that differences in schooling appear to explain a large portion of ...

Although the photographs did show twins with a difference in sun exposure, a study involving the perceived age differences between identical twins did not say that one of these twins smoked and the ...