It is healthy for girls to dream of having high-flying careers and families, but schools must teach them about the realities of having children and juggling priorities, a leading proponent of girls' education has said.
Jill Berry, president of the Girls' Schools Association (GSA), said it was "healthy" for girls to aspire to a "flash sports car with a baby seat in the back", but schools had to prepare young women early for the challenges and choices they would have to make in life.
Speaking before the association's annual conference in Harrogate next week, Mrs Berry said girls had come to expect equality of opportunity, but needed to realise that their lives would be more complicated than simply "having it all".
She told The TES: "They will need to realise that there may be times when they might not want to work, or they might want to take a lesser job because their priorities have changed. It is important that they leave school at 18 with their eyes open."
It was vital, she said, that girls did not feel guilty about taking time out, or failing to be brilliant professionals, mothers and wives all at the same time.
"Your priorities shift but you're not selling out, you are facing reality and trying to be realistic about what you can achieve and you should stop beating yourself up about it."
Mrs Berry said the message of previous decades, encouraging girls to aim higher at all costs, was no longer appropriate and made their lives seem more simple than they really are.
"Most women cannot keep all the plates spinning," she said; "sometimes the plates crash."
But equally, she said, girls should be taught that they can compete with men professionally, and should strive to be independent.
"When my pupils try to wind me up by saying they plan to marry a rich man to support them, I ask them 'what if he runs off with the au pair?'"
The head of Dame Alice Harpur School in Bedford said high-achieving girls were well prepared for pacing themselves in life after dealing with the challenge of meeting their social, sporting, musical and academic commitments at school.
Mrs Berry's comments come amid national debate over enhanced maternity leave and flexible-working rights.
One of the city's leading hedge fund managers, Nichola Pease, claimed recently that the new right to 12 months' maternity leave was discouraging international employers from recruiting British women.
Among the other key speakers at the GSA conference are Susan Vinnicombe, director of the International Centre for Women Leaders, and Steve Munby, chief executive of the National College for Leadership of Schools and Children's Services.
The GSA represents the heads of the leading independent girls' schools, which educate around 110,000 girls. It provides free advice on educating and raising girls on its website mydaughter.co.uk.