"sex difference" is a correct and usable phrase in written English.
You can use it when discussing the differences between the sexes, such as in the phrase "the sex difference between boys and girls".
But biology cannot entirely explain the sex difference.
There was no significant sex difference on Digit Span.
Other studies have questioned Jensen's null sex difference theory.
No sex difference in root resorption was found.
The sex difference shrinks by age 35, then prevalence drops.
However, there was no sex difference in autoantibody persistence in the dogs affected with hypoadrenocorticism.
The results showed that the number of inputs required estimating outputs varied with sex difference.
In contrast, no sex difference characterized topological information processing (object-to-position assignment).
It allowed us to find a sex difference in the DA signature of cigarette smoking.
There was no sex difference in facial recognition, consistent with earlier studies.
We found a moderate sex difference on both hands and high temporal stability.
