I mean, his alien forms have shown to be able to change or control him if he used them for too long. Like the shenanigans that happened with Ghostfreak becoming self-aware, or when he got pregnant with Big Chill babies and kept involuntarily transforming into Big Chill to make them a nest. He definitely could end up becoming a Xenomorph Queen by accident, eventually destroying the world with his brood.

As someone who's never watched Ben 10, reading this comment was a trip. O_o