twins fraternal

基本解释

The notion that the twins are fraternal symbolizes the union between the feminine and masculine aspects of yourself.
双胞胎是你自己女性和男性方面结合的对偶标志。
But importantly, the chance of both twins being affected by autism was not low among fraternal twins, which is counter to what would be expected if genetics were the dominant factor.
但重要的是，在异卵双胞胎中，两个孩子同都患自闭症的概率也不低，如果基因因素是主要因素，那么这种情况就与我们期望的结果是相反的。
The investigators then determined the differences in autism concordance rates between the identical and fraternal twins to estimate the contribution to autism of genes and of a shared environment.
研究者决定同卵和异卵双胞胎自闭症一致几率的区别，估计自闭症的病因是基因还是共享的环境。

This means that behavioural traits with a large genetic component are more likely to be shared by identical twins than fraternal twins.
ECONOMIST: Evidence that psychopaths are born, not made
They used the classic trick of neutralising the effect of upbringing and exposing that of genetics by comparing identical twins (who share all their genes) with fraternal twins (who share half).
ECONOMIST: Evolution
Conversely, those traits with a large environmental component will be shared by identical and fraternal twins in equal measure.
ECONOMIST: Evidence that psychopaths are born, not made