Insurance companies being forced to assess female and male motorists in the same way may end up charging women an extra £1,000 over current levels.
On March 1, the European Court of Justice may rule that setting different rates of insurance cover for women and men is illegal.
Female drivers aged 17-22 currently pay an average £1,682 a year because they are safer drivers statistically. Males in the same age bracket pay an average £2,750 because they are 10 times more likely to be in a crash and as much as 25 times more likely to break the law while driving.
If the rates are equalised, insurers are more likely to raise costs for females rather than reduce costs for males.
A spokesman for the Association of British Insurers said: "We believe this will be extremely detrimental to UK consumers. If insurers aren't able to take into account risk factors, it will have widespread implications.
"Insurers may look to other risk factors that give an indication of gender, for example occupation or vehicle type, but if this is considered indirect discrimination it is unlikely to be permitted."