It's what every expectant parent wants to know - who their baby will look like.
每个充满期待的父母都希望知道自己的孩子会长成什么样。

And this fascinating video goes some way to showing how.
而这个有趣的视频将告诉你人脸是怎么形成的。

Produced for the BBC series Inside the Human Body that was aired last year, the animation is based on scans of a developing embryo and captures the formation of the face in the womb.
BBC去年公布了这部探秘人体秘密的系列视频，其动画场景是根据对胚胎发育过程的扫描以及子宫内部人脸的形状捕捉影像而设计的。

The video reveals how sections of the face grow and fit together like a puzzle just three months after conception.
视频解密了怀孕前三个月人脸发育成型的过程。

BBC’s Michael Mosley said: 'The three main sections of the puzzle meet in the middle of your top lip, creating the groove that is your philtrum.'
BBC的Michael Mosley说：“谜团的重点主要集中在上唇中部的发育，以及其周边皱纹的变化即人中的形成。”

The 30-second clip strings together 3-D models of the developing face based on scans taken in the first trimester.
30秒长度的影片串联起不同发育阶段的3D人脸模型，这些都是根据孕期前3个月扫描影像编辑设计的。

'It was a nightmare for structures like the nose and palate, which didn’t exist for most of the animation,' graphics researcher David Barker told New Scientist.
影像学研究人员David Barker对《新科学家》杂志表示，动画中没有出现类似鼻子和下颚的形状，看上去非常可怕。

'Their formation is a complicated ballet of growth and fusion of moving plates of tissue.'
他说：“组织的发育和融合过程如同芭蕾舞般复杂。”

Plates of tissue that fuse at the philtrum, which can be long or short and deep or shallow, depending on a person’s genetic makeup.
皮肤组织在下颚处聚集。这个地方可长可短，可深可浅，其具体形状是依据基因构成而变化乃至最后成型。

The failure of those plates to fuse can cause a cleft lip or palate. And a smooth philtrum can signal disorders like fetal alcohol syndrome.
如果这块皮肤组织没有发育好，那就会形成唇裂或者颚裂。而如果人中部分过于平滑就表示可能患有胎儿乙醇综合征或其他类似的肌体紊乱。

'This whole amazing process – the bits coming together to produce a recognisable human face – happens in the womb between two and three months,' said Mr Mosley. 'If it doesn’t happen then, it never will.'
“这一整个令人惊叹的过程丝丝剥茧，最后呈现出一个人脸的基本轮廓。这一系列过程都是在怀孕第二到第三个月，在母体的子宫中完成的。” Mosley说，“一旦跳过这个过程，生命就无法继续成长。”