Women have benefited from smaller car insurance premiums due to their lower accident rates, and predictions as to how they will be affected have varied widely.
Some analysts believe younger women could see their premiums almost double, while others forecast that the increases could be more gentle than expected.
Young women are likely to bear the brunt of the increases, due to the higher accident rates of young men, which experts warn could force many younger female drivers off the road.
Meanwhile, some men could see a small reduction in their premiums.
New European rules come into force today which mean some women are set for a shock when their next car insurance quote lands on the doormat.
The new gender-neutral rules stem from a European Court of Justice ruling last year which means insurers are no longer able to consider a customer's gender when calculating how much they pay for their car or life insurance, or what their retirement income should be.