Children should be taught in school about infertility as well as about avoiding pregnancy, according to the new head of the Human Fertilisation and Embryology Authority, who is concerned that few young people realise the difficulties they could face in trying for a family.

Lisa Jardine's concerns include the issues couples face over infertility brought on by factors such as obesity.

Jardine, professor of renaissance studies at Queen Mary, London University, says infertility is too little discussed. "You've got to start it at school," she said. "If one in seven of us in the modern world is going to have problems with infertility then instead of all the teaching at school being about how to stop getting pregnant someone had better start teaching about how you do get pregnant, because there are going to be a lot of extremely disappointed people out there."

She warns of a growing problem. "I think male fertility is way down. There are probably all sorts of ecological and environmental reasons why we are less fertile." She said children at school would be told it is incredibly easy to get pregnant and that they had better be careful. "I think we could take that opportunity to talk about what happens if it isn't easy. In other words, that would make it less of a dreadful threat if you did not get pregnant," she said.

Recent figures from the HFEA show that more than 32,000 women a year get fertility treatment, leading to more than 11,000 births. Studies have shown that female obesity dramatically lowers the chance of conceiving and raises the risk of serious complications during pregnancy.

The British Fertility Society issued guidelines to IVF clinics last year advising starting treatment on severely overweight women only once those women had cut their body mass index to below 35. Women under 37 years should cut their weight further, to a BMI of less than 30, the guidelines stated. A woman with a BMI above 35 was half as likely to get pregnant as a woman whose BMI was less than 30.

Some experts believe obesity could be a factor that will drive one in five couples to seek fertility treatment within a decade.

Jardine wants more widespread knowledge about fertility treatment. She said clinicians can be surprised to find women are unaware of what IVF entails. Yet treated women will probably not be able to work and need daily injections. "They will be given chemicals that disturb their hormonal balance, possibly permanently ... they have scans that are intrusive and surgical procedures that are thoroughly invasive, and, at the end, if lucky, get a baby."

Jardine believes there should be more open discussion also on scientific research involving embryos.