I've noticed in recent Australian data that tests of ability show that boys don't lag girls overall - in fact they have a handy lead in Maths etc. It’s only when you turn to test scores based on more subjective teacher assessment that girls jump ahead. Unfortunately I have not (yet) compiled the data into a presentable format but Richard Reeves has just done so for US data - https://aibm.org/research/boys-girls-and-grades-examining-gpa-and-sat-trends/

What he finds is that boys have a slight overall lead in SAT (a more objective test of ability) and a handy lead in math. However if one turns to more subjective teacher based assessment (GPA) then girls have a significant lead – 3.23 vs 3.0

Interestingly Reeves does mention teacher bias but surrounds it with a feminist smoke screen. He does at least point out that GPA is a better indicator of academic performance so emphasising it in university entrance would make sense and help level males and females.

PS: For any of you who aren’t familiar with the topic, the underlying issue is that teachers discriminate against boys in marking. For past posts on the topic see Here and Here