Michael Schoch, Answers questions on Noodle
You may want to check out the answers to this question about the benefits and drawbacks of attending an all female college. While high school is different from college, it may provide some useful insight. Similarly, the Noodle profile for Scripps College has other student and alumni responses that touch on the pros and cons of single-gender schools.
Another interesting resource is the National Association for Single Sex Public Education, which explains the pedagogical and social benefits of all female schools.
I would also suggest calling Our Lady of Tepeyac High School and asking the admissions department there what it thinks the benefits of an all female education are. The school may be able to put you in touch with alumni and other parents who can offer their own personal testimonies.
Good luck and feel free to ask more questions as they come up!