yī / shēng / jiǎn / chá / hòu / fā / xiàn / tā / men / shì / tóng / luǎn / xiōng / dì / jī / yīn / wán / quán / xiāng / tóng

医生检查后发现他们是同卵兄弟，基因完全相同。

The doctor found after examination that they are identical twins with completely identical genes.