Gregor's transformation into a giant bug touches on larger issues of identity for himself and his family. One way of approaching the identity issue is to consider whether Gregor is still Gregor if he looks like a bug. Sure, we as readers of The Metamorphosis have access to his thoughts, but his family doesn't. So let's put another twist on the identity issue: is Gregor still Gregor if he has no way of communicating his thoughts to others, if the others have no way of verifying that he is indeed still Gregor? And the cleaning woman's treatment of Gregor brings up yet another issue: why is it that the cleaning woman, and not the family, is so willing to ascribe to Gregor human qualities such as intelligence and intention? So let's put yet another twist on the identity issue: who has the right to say whether Gregor is Gregor or not? Who gets to identify Gregor by name, and who gets to take his name away?
By showing how much Gregor's identity is affected by the others' treatment of him, the story shows how identity is socially constructed, rather than an inborn trait.
The most significant consequence of Gregor's transformation is not his insect form, but actually his loss of language; without language, Gregor loses the power to express who he is and control his own life.