Boys are being failed by schools because lessons have become too "feminised" in recent years, an academic is warning.
More male teachers are needed to inspire boys, it is argued
Dr Tony Sewell is calling for more nurturing of traditional "male" traits, such as competitiveness and leadership.
Schools focus too much on "feminine" qualities such as organisation and attentiveness, he was telling an NASUWT union conference in London.
The government said it was working "to better engage" male pupils.
Dr Sewell, a former lecturer at Leeds University, says some coursework should be replaced with final exams and there should be more emphasis on outdoor adventure in the curriculum.
Dr Sewell says some boys find lessons frustrating
He also wants extra efforts to recruit more male teachers and to introduce more "excitement" to lessons.
Dr Sewell told the BBC News website: "On the one hand, boys have to adapt to the world they are living in, which is not all about muscle and machismo.
"On the other hand it's clear many of their needs are not being met.
"We are often frightened by the traditional idea of the male, where we think it's wrong to be overtly competitive, and boys often lack an outlet for their emotions.
"Young women have lots of support, with magazines and programmes devoted to them, and boys often do not."
Dr Sewell is calling for science lessons to include more practical experiments to interest male pupils.
He said:" The girls seem more able to adapt to more theory-only learning, while boys want more action. They want to blow things up and see science in action.
"I'm not suggesting that there aren't many lazy boys out there, but there needs to be more done to attract males to learning."
Some boys are turning to gang violence as an outlet for their frustrated masculinity, he said.
Male pupils' exam results lag behind those of girls.
In 2004, 63.3% of female GCSE entries resulted in an A* to C grade, compared with 54.9% of male entries.
A Department for Education and Skills spokesman said: "We are delivering a curriculum and school experience to better engage boys in education.
"Massive investment in personalised learning, as well as reforms to 14-19 education, will deliver catch up classes, challenge for gifted and talented pupils, and a new curriculum to keep both boys and girls engaged and excelling in learning."