The younger the driver, the greater the gender-related discount. Young men have accidents often, and cause a lot of expensive damage. Female drivers, particularly those under the age of 40, are likely to have fewer accidents. They account for just 2 per cent of dangerous driving offences and 6 per cent of drink-driving convictions.
Claims made to insurers suggest that marriage has a calming effect on young men, and some providers reflect this in lower premiums.
"It's a question of the civilising influence of women. If young men are single, they may be out on the town with more money to spend and more social life in the evenings," said David Stevens at Admiral, one of the telephone-based motor insurance providers.
Young women pay the same, regardless of their marital status.
To capitalise on the difference, some insurers have launched women-only policies, offering lower premiums in certain niche areas. For example, Sabre's limited mileage Lady Select policy, through the insurance broker, Swinton, offers good value for third-party, fire and theft cover.
Research also shows that women are more cautious and courteous on the roads. Their speeds tend to be lower, so when women have accidents less damage is done. "Women also tend to be less aggressive," said Alan Woodcock, at Sabre.
However, the principal reason for reduced risk and, therefore, lower premiums is mileage. The average woman covers half to three-quarters of the distance a man drives each year. Less time spent on the road leads to fewer accidents.
At the same time, break-ins may increase slightly if cars are left parked in the road rather than being driven.
Insurers display deep anxiety about young male drivers. Eagle Star, through RAC, charges some 18 year olds double their female counterparts. Young men's excesses can also be higher, and costs often shoot up when insuring them as named drivers on other people's policies.
By the age of 30 or 35, most policy costs even out - with some exceptions. East West policies for women through Telesure maintain a 9 per cent advantage even at the age of 55. A policy from Sabre, through Swinton, for a 55- year-old woman insured for third-party, fire and theft costs 22 per cent less than the equivalent policy for a man of that age.
Women with serious accidents or driving convictions are often refused female driver discounts.
Other brokers and insurers offering special policies for women include Provident, which has Lady Driva, Young Lady Driver and Second Car Cover. All three give competitive quotes for older cars parked outside homes in low-risk areas.
The RAC is about to launch a new policy aimed at the more traditional female lifestyle - the second car driver, with only limited mileage.
The benefits of this will include special medical cover if children are injured in car accidents and a replacement car for school runs should an accident occur. There will also be lower premiums in recognition of the low mileage.
Norwich Union's Lady Motoring prefers to add value. It offers free RAC membership, worth about £100, and cover to carry schoolchildren "for hire or reward".
Of course, the best deal for women may not lie with these specialist policies. Each quote depends on an insurer's perception of the individual's risk.
It pays to try a few brokers - such as AA or Telesure - as well as direct insurers - such as Admiral or Direct Line - before making a choice. OneQuote, on the other hand, will shop around to find the best product overall through a broker.
Cheaper cover for female drivers
Provider 20-year-old female 20-year-old male
Cost £ Insurer Cost £ Insurer
0800 444777 436.25 Gan Alpha 505.25 Gan Alpha
0800 600800 467 Admiral 496.28 Admiral
081 686 2468 444.85 Direct Line 444.85 Direct Line
Broker/local branch 722.63 General Accident 836.40 General Accident
071 639 9734 308 Touchline 350 Touchline
Through broker 964.52 Norwich Union 992.20 Norwich Union
0891 515515 404.87 Minster Insurance 470.40 Minster Insurance
Through broker. 436 Lady Select 1386 Sabre
0800 300800 510.56 Sun Alliance 510.56 Sun Alliance
Local branch 436.89 Bishopsgate 549.40 Eagle Star
081 665 9988 335.18 Bradford Pennine 480.27 Eagle Star Quotes for factory engineer with 2 years no claims bonus, driving G reg Vauxhall Astra 1.4, in SN2 postcode area, with £100 excess. Drivers may incur up to £400 additional excess.Reuse content