Dozens of schools in London are taking part in the initiative, organised by local health authorities and the Brook Advisory Centres.
Each girl is encouraged to look after an egg for a week as if it were her own baby. She prepares a carrycot, lined with tissues, which she keeps with her at all times. The girl feeds and changes the egg six times a day, by replacing the tissues, and keeps a diary of the egg's progress.
Instructions issued to pupils aged 14 and 15 at the Maria Fidelis Convent School in Camden stress that the egg must go everywhere with the girl during the exercise.
"If you go out, you may put your egg in your carrycot in your bag but remember never to leave your bag unattended and don't swing your bag about as you may break the egg.
"If you break your egg you must tell someone at home and pay a pre-arranged fine (perhaps the price of an egg) or do a household chore. Record it in your diary, stating how you broke it, how you felt about it and the reactions of the person you told. Get a new egg and continue with the exercise."
A Camden council spokeswoman said it was part of a sex education project that was often followed up by encouraging the teenagers to look after dolls simulating babies.
"We all know about the huge problem of unwanted teenage pregnancies. This is an imaginative project designed to get teenagers to really think about the consequences of unwanted pregnancies."
A Family Planning Association spokeswoman said the recent storm about teenage mothers and adoption had highlighted the problem of unplanned babies. The association wanted improved and more widespread sex education.
A Brook Advisory Centre spokeswoman said the project involved schools in Camden, Islington and Southwark. Young mothers and fathers also talk in schools about the realities of being a teenage parent.Reuse content