In most bird raptor species, the female is larger than the male. This goes against conventional biology logic for nearly every other bird/mammal/lizard species, but it is indeed the case assuming you're basing T-rexes off a raptor.

But you were probably thinking of velociraptors. Given the initial size of T-rexes, there wouldn't be an evolutionary advantage for a T-rex hen to be notably larger than a T-rex drake (or whatever the sexes are called), since anything that might attack their nest is getting squashed anyways.

In most bird raptor species, the female is larger than the male. This goes against conventional biology logic for nearly every other bird/mammal/lizard species, but it is indeed the case assuming you're basing T-rexes off a raptor.

But you were probably thinking of velociraptors. Given the initial size of T-rexes, there wouldn't be an evolutionary advantage for a T-rex hen to be notably larger than a T-rex drake, since anything that might attack their nest is getting squashed anyways.