Also, VGR: "The Q and the Gray" established that the Q had never procreated before. Since Trelane had parents, that's incompatible with the idea of Trelane being a Q.
Which was a strange thing for Voyager to do given that a previous TNG episode establish that a pair of Q did produce a child. The Q child didn't realize she was Q, until Q pointed it out to her.
While the Q parents gave up their power prior to creating a child, it shows that Q can change themselves in order to reproduce.
And it might not have been necessary for them to have given up their powers.