As a member of the Texas Christian University rifle team, junior Sarah Scherer competes against some of the best female—and male—shooters in the country. But when she competes in the second round of the Olympic trials at Camp Perry, Ohio, this weekend, she'll only be competing against other women.

Why is that? Is it still unfair for men and women to compete against one another—even in sports where size and strength matter little? Or is it just latent sexism?

Shooting...