This is an example of twinning or gemination. Here are some more examples.

这孪生或双生的一。 这里还有一些。

He's also one of the principal investigators of the twin study.

他也双生研究的主要研究者之一。

The doppelganger? -Evil twin shadow person.

重身？-不详的神秘双生者。

One of the hugely surprising findings from behavioral genetics is how alike identical twins reared apart are.

行为遗传学的一巨大的惊奇发现， 被分开教养的同卵双生也多么相似。

For instance, monozygotic twins look more alike than dizygotic twins and maybe they have different and--they have more similar environments because of this similarity in appearance.

比如， 单卵双生的相貌更相似， 可能因为他们有着不同的、更相似的环境。

Thanks to research like NASA's twin study which you'll hear about in a minute, scientists are getting an idea about how extended time in space effects people.

多亏了下面将介绍的美国航天局的双生研究，科学家们正在了解长时间在太空中生活对人类的影响。