> “People have been making this assumption that we can use male mice to reliably make comparisons within and across experiments, but our data suggest that female mice are more stable in terms of behavior despite the fact that they have the estrous cycle,” Datta said.

Isn't this quote mixing up two uses of "stable"? They stuck with male mice to be able to compare to other studies, not to reduce variability within the study (which should not be a goal in itself).

If this shows anything, it is that we know way too little about biological factors underlying behavior, and that variation in other factors (age is an obvious one, but there are also genes that affect this behavior) should be investigated too.