Article here. Excerpt:

'WELLINGTON (Reuters Life!) - Boys get better grades at single-sex schools than when they're in mixed-gender schools, where girls consistently outperform them, a recent New Zealand study shows.

The study, based on the long-term Christchurch Health and Development Study at the University of Otago, compared the educational achievements of over 900 boys and girls who attended single-sex and coeducational secondary schools in New Zealand.

For students attending single-sex secondary schools, there was a slight tendency for males to outperform females.

For students attending co-educational schools, however, there was a clear tendency for girls to outperform boys, a pattern that continued when students were followed up to the age of 25.'