Women GPs earn £11,000 less than men for doing the same job, a report reveals.
The 13 per cent pay gap is only partly explained by women's family commitments.
Male GPs earned £83,333 on average in 2006, while women earned £72,250.
In The Pay Gap for Women in Medicine and Academic Medicine, co-published with the BMA, the Medical Women's Federation (MWF) suggested that women are reluctant to bargain their pay up.
Academic research hints that 'women are poor or unwilling negotiators', the report said.
Dr Clarissa Fabre, MWF president-elect and a GP in Uckfield, East Sussex, agreed: 'Women do not like to bring up money or, for example, time to parity. It is in their nature not to ask. They want something that is convenient for their lives. Men are much more forward about it.'
The MWF said half the pay gap is explainable. Men's earnings outstrip women's because they are more likely to take on extra work, Dr Fiona Cornish, MWF member and a GP in Cambridge, said.
'In my own practice there are three women and two men. We all earn exactly the same rates but the men do far more out-of-hours,' Dr Cornish said.
The MWF report found an 8 per cent pay gap among trainees. But GP trainees do better than other doctors. 'In this cohort, there appears to be a significant salary premium for women associated with working in general practice,' the report said.
Dr Cornish added: 'I do not think there is any discrimination against women in general practice in pay.'
GPs made up 6 per cent of the 1,162 doctors who completed a pay survey of women in academic and clinical medicine.