As the whole thing was entirely f**ked up with the Human DNA and the blah-de-blah! If the Newborn were to take on the 'groqin' aspects of the Human, then it would of become a lot bigger, however considering how it was all mixed and screwed up, i think it would of possibly got slightly bigger, maybe a few Alien features, nothing to drastic, and then stayed liked that, but considering how screwed up the majority of A:r is....well i wouldnt of been surprised if the writer invisioned it as a 50 foot tall GOJIRA!