What do you think of single sex schools?

What do you think about single sex schools?
Are they the answer?
Fascinating story this month in the New York Times about Leonard Sax and single sex schools.

Leonard Sax wrote a terrific book called Gender Matters, which establishes that many of the differences between boys and girls are neurological. 

Read the article. Fascinating information.
Sax advocates for single sex schools. 

What do you think about single sex schools? Are they the answer for either boys or girls?