What with Demi Moore and Madonna having husbands who are respectively 16 and ten years younger than they are, the toyboy is certainly an uncontroversial member of the celebrity landscape.

For the rest of us, relationships in which the woman is several years older than the man are also more common and accepted than they were.

Julia Macmillan is sure she has spotted a trend - and with it a business opportunity.

In the next few weeks she will launch www.toyboywarehouse.com, the first online lonely hearts agency to cater just for relationships in which women are the older half. Men will only be able to search for women at least a year their senior, and women likewise for men more than a year their junior.

Macmillan is 42 and her boyfriend is 36. She estimates that more than half of her female friends are going out with younger guys.

"Often when men get into their 40s they get stuck in their ways and a bit boring," she says. "Younger men are livelier, sexier and fun to be with. And they make you feel you are not losing your attractiveness." The site is based on the premise that a certain type of woman prefers a younger man.

But, for it to work, the opposite also needs to be true - that there are men who prefer older women. Do enough of these men exist? "I'm fancying older women more than I used to," says Adam, 40, a lawyer from West London. "They are more stimulating."

Men are generally not programmed to find woman sexually attractive who look much older than they do.

True, there are exceptions. Men of any generation would probably let themselves be seduced by Madonna if the chance arose. But that is because these women are rich and famous and they also hardly look their age.

Toyboywarehouse.com may well turn into a site where the difference between the sexes is not just one of years but also of wealth and status.

Women are certainly a lot richer and more independent than they used to be.

Chris, 39, from North London, thinks it's fine to date older women but there is a cut-off-point - about 50: "That would be beyond the pale."

When I was 28, I went out with a 33-year-old. Whatever she had lost in pertness, she had certainly gained in sexual confidence and technique.

We might think we covet youth in a partner but when it comes to whether the sex is any good or not, experience often counts for more.

My time as a toyboy ended for reasons nothing to do with my girlfriend's age.

Now I am in my mid-30s I don't want to go out with anyone over 40. That's because I'm looking to breed. But, according to Macmillan, many men - and women - have decided against having a family, and it is these people who are suited to becoming toyboys.

Going out with an older woman forces you to think about the present and not the future, says Grant, 35, a teacher, from Bethnal Green.

"You can have a warm, loving relationship with someone much older.

"But I don't think they have as much chance of long-term success as going out with someone your own age."

I suspect there will be more women than men joining toyboywarehouse.com.