> I would like the article to answer this: how well do the kids in the single-sex schools do later on in life ...

A little googling led me to this article about a study which looked at the same:

http://newsroom.ucla.edu/portal/ucla/graduates-of-all-girls-...

And what I thought would be of interest to us here:

In an indication of greater, though still low, interest in the field of engineering, alumnae of single-sex independent schools are three times more likely than those from coeducational independent schools to report that they intend to pursue a career in engineering (4.4 percent vs. 1.4 percent).