Of course, it is possible to have evil desires. If our desires are evil then the remedy is penance and conversion. If you don't eradicate the cause of the desire, which is sin, it will become your master. And of course it is blasphemy to suggest that God could create someone as a ɧoɱosɛҳųαƖ. That's like saying God created a psychopath to be a psychopath.
Really, its not so much about saying that God created them that way as denying the Creater himself, since 'male and female He created them".