Boy pupils in schools in Wales can reach the age of 11 without ever being taught by a man, according to a report.
The General Teaching Council for Wales said that unless more men are recruited into the profession, boys could be denied classroom male role models.
It said only 26.9% of teachers in all schools in Wales are men. In primary schools the figure is just 16%.
Secondary schools have the highest figure at 40%. However, most Welsh head teachers are still men.
The teaching council’s report found schools in Wales had a gender imbalance due to the shortage of male teachers.
Men were still under-represented despite a push by the Teacher Training Agency in 2002 to recruit more into the profession.
The proportion of male teachers has fallen from 28.1% in 2002. However, in the latest the intake of newly qualified teachers, the figure rose to 29.6%.
Gary Brace, chief executive of the General Teaching Council for Wales, said people’s perceptions about primary school teaching may need to change to encourage more men to apply.
He said it was possible that some men had worries about the possible dangers of working with children.
He said: “It’s a self-perpetuating situation where the perception of primary teaching in particular is that it’s a female profession, and therefore men might not be attracted to the social experience of the primary staff room.
“Secondly, it’s a more serious unfounded but understandable perception, a result of the child safety concerns that we have, that possibly males who choose to work with young children might come under suspicion.
“Thirdly, there’s some evidence that males are not very good at applying for teacher training courses and by the time the date (for course to start) comes, they are more or less filled.”
However, men are still ahead in the head teachers’ league, holding 50.1% of posts.
In secondary schools, 81.4% of head teachers are male. Primary schools have more woman head teachers, at 54%.
Mr Brace was optimistic that more women would become head teachers.
He said: “I think things will change very soon because from this September there will be a mandatory qualification to be a head teacher.
“If the majority of your teaching profession are female, and you have to have the qualification, then more females will come through to headship in due course.”