MALE primary teachers, it seems, are doing very little to ensure that school rolls remain buoyant.
A University of North London study has revealed that they produce fewer children than male secondary teachers. Women primary teachers also have larger families.But the research suggests that it is male primary teachers' bank balances - rather than a low sperm count - that lets them down.
While a relatively low income may reduce the male primary teacher's opportunities to become a father, it seems women teachers are more likely to benefit from partners with superior salaries to bring home the extra bacon.
Alistair Ross, author of The career histories of London teachers, says: "Male primary teachers have fewer children than their female counterparts, or their male secondary colleagues. It is possible that economic considerations may help explain this.
"There are fewer promoted posts with higher salaries available in primary education, even though men have taken a disproportionate share of such posts."
Their sense of frustration is no doubt heightened by the fact that, on the face of it, they have a far better chance of finding a partner at work, being vastly outnumbered by women in the staffroom.
But female secondary teachers also appear to be relatively unproductive. Half of those questioned who had started teaching between 1971 and 1974 had no children.
Of those teachers who completed their training or took up posts between 1989 and 1992, women, on average, had their first child after three years in the job and men after four. Thirteen per cent of men had at least one child by the time they started teaching, compared with 23 per cent of women.
Perhaps the best advice for men is to forget their colleagues and look elsewhere for a mate. Teachers are among the 10 most popular choices among women using the dating agency Drawing Down the Moon, putting them alongside architects and surgeons.