Canadian researchers have found the first evidence that older brains remember information better if it is learned through trial and error, rather than passively taking it in, a study said.

London - Their first date was lunch followed by a kiss. Four months later, a blissfully happy Christine Rae was walking down the aisle.

Given that Christine found her husband Chris on an internet dating site, this was a very 21st century romance.

But no young lovers these. Christine was 62 and Chris, 61. Both had children, grandchildren and failed marriages behind them.

And it’s not just the internet’s involvement that makes their romance so very modern. Chris and Christine waited only one date before they ditched the formalities and slept with one another.

They are just one of many couples in a generation of over-40s who are throwing caution to the wind when it comes to getting between the sheets with a new lover, despite the danger of a broken heart ... or sexually transmitted disease.

“It was a risk - after all, I had only recently met this man and he was effectively a stranger,” admits Christine, a retired mother-of-two from Suffolk.

“But I felt like there was an immediate connection between us. People think that just because we are in our 60s, the sex doesn’t matter. We may not be as agile as they are - we joke about our respective bad backs - but sex is just as important to us as it is to young people,” she says.

If the statistics are to be believed, these two besotted sixtysomethings are not the only ones behaving like rash teenagers after meeting online. Not only is internet dating now a common way for middle-aged men and women to meet, it seems these silver surfers, as they’ve become known, are jumping into bed far quicker than younger lovers.

Indeed, one survey by dating website eHarmony found that singles over 50 are twice as likely to have sex on their first date.

Relationship psychologist Susan Quilliam, who rewrote the Joy Of Sex, explains: “This is a generation that have been largely faithful for 20 or 30 years who now find themselves rediscovering desire. They may not have had a very good sex life with their long-term partner, so this newfound passion can be very exciting and liberating.

“It’s not that these women want a one-night stand. They almost always want a long-term relationship, but they rush into sex because they are looking for some sort of connection.”

These new relationships are no doubt exciting but, as the younger generation has discovered, casual sex in 2011 is far from risk-free.

According to government statistics, there has been a dramatic rise in the incidence of sexually transmitted infections (STIs) in the over-40s since 2000. Experts blame this on the fact that the older generation assume they don’t have to worry. They no longer have to consider contraception, and they assume they no longer have to think about safe sex either.

In fact, such is the scale of the problem, experts are calling for sexual health education to be specifically targeted at what they are dubbing Generation Grey Sex.

For those like Christine and Chris Rae who have been out of the dating game for a while, the rules have changed quite dramatically.

Christine, who was married for 21 years to her first husband and seven years to her second, had been single for five years when she met Chris and she admits she had almost given up on finding love again until she spotted his details on an internet dating site.

“I’d tried dating through agencies in newspapers and had quite a few disappointments. I met one chap for coffee and the moment he walked into the cafe I thought: ‘I really don’t trust this man.’ He would not look me in the eye and seemed very shifty. I made my excuses and left.

“Many times I thought: [Why am I doing this?’ I had a new granddaughter, and in fact I was on the point of giving up when I spotted Chris’s photo on a dating website.

“Immediately I was attracted to him. He was leaning back in a garden chair. I thought he had a lovely smile so I got in touch with him. We met two weeks later and in person, the attraction was even stronger. On our first date we had lunch and walked around Bury St Edmunds.

“I was as nervous as a teenager but I felt like there was such a connection between us. During our lunch, I had reached out to touch his hand, and he didn’t pull away.

“As we chatted away, I thought it was such a shame the date was coming to an end that I said: ‘Why don’t you come back to Cambridge with me?’ Back at my house, we had a kiss and a cuddle, which I know was terribly forward, but I just felt so comfortable. He left at about 7pm.’

A week later, the couple met again and this time, Chris stayed over. It was a decision which they insist felt “very natural” and their only concern was how their children might react to the news. Christine waited six weeks before introducing her lover to her two adult daughters.

“To my relief they took to him at once and I was really touched when one of my daughters said: ‘He’s lovely, Mum.’” Chris proposed after whisking Christine off for a holiday in Portugal and they were married within six months of that first date.

“I said yes straight away,” says Christine. “Why wait? At our age, what’s the point in stalling for two years? You might as well leap in.”

Fresh from the break-up of a 21-year relationship, Gabrielle Stirling is another midlifer who rushed into bed with an online date.

The 44-year-old businesswoman from Brighton went looking for love on a dating site called Match.com. “I’d chatted to a few men online but had not been on any dates when I spotted Dave’s profile,” she says. “It was the first time I’ve used an online dating website. Dave struck me as intelligent and articulate.

“As he lived only 15 miles from me, we arranged to meet in Brighton and had a magical day going for a meal, drinks and walking about the town. We held hands almost straight away - I can’t explain it, we just had this connection and he made it very clear that he found me attractive.”

Even though Gabrielle liked Dave, 42, she didn’t expect their relationship to become sexual quite so fast.

“After that first date, I invited him over for supper and he ended up staying,” she says. “I’ve only ever had a handful of sexual partners and so it was a really big deal for me,’ she says. “I didn’t think I would sleep with him so quickly, but it just felt so natural and I had this sixth sense that our relationship was going to be much more meaningful than just sex.

“On our third date, he took me home to meet his children. They were wary at first. I was terrified, but they were very friendly and now I love them to bits. I’m just about to move into his home - for some people, this would be too quick, but when you’re over 40, you know what you want in life, and you just go for it.’

This sense that time is running out also seems to be driving Judi Turburfield, 45, a reflexologist, who is getting married to sales and marketing manager Dave Davies, 44, in four weeks time - just six months after meeting him online.

“Initially my family and friends were very concerned at how quickly my relationship with Dave was moving,’ she says. “My children kept asking me: ‘Are you sure you can trust him?’

“There’s no doubt there are some confidence tricksters out there on the internet and as a single woman, you have to be careful. But with Dave, I trusted him instinctively.’

At no point during any of these whirlwind romances did it seem to occur to these women to worry about “safe sex”.

“I just trusted him and knew it would be OK,’ says Chris. “I felt that he was a gentleman and he would take care of it.’

Judi admits it did take some courage to ask Dave if he would take precautions: “It was embarrassing but he said he would take care of it,” she says.

These women are lucky. But many others are paying the price for rediscovering passion.

The rise in people over 50 having sex with new partners has led to an increase in all of the five main sexually transmitted infections in those age groups.

Last autumn, the Family Planning Association launched its Middle Age Spread campaign using adverts from the Sixties and Seventies to encourage baby boomers to use condoms.

“We are talking about a generation who didn’t receive much sex education when they were young,’ explains Susan Quilliam. “It simply doesn’t occur to many that they might be at the same risk of infection as a teenager.’

One of the unlucky ones is 52-year-old health worker Rosemary Benson who caught a STI after a holiday fling.

“I had just come out of a very safe and loving ten-year relationship and looking back, I suppose I was very naive,’ she admits.

“When I was young, there was not such a high incidence of STIs, so it just didn’t occur to me I was putting myself at risk when I fell into bed with a very good-looking Englishman I met on holiday in Jamaica.

“My sister lives there and I was introduced to this guy, a businessman, through mutual friends. I was warned that he had a reputation for being a ladies man but I was so flattered that he was interested in me.

“I simply did not think - I trusted him, and at the time I was emotionally quite raw and vulnerable after the end of a relationship and wasn’t thinking straight. When he invited me to see his home, one thing led to another and we ended up in bed having unprotected sex.

“We had three full days together, and they were heady and exciting. I didn’t think I was putting myself in any danger, although my sister was worried that he might hurt me emotionally.

“At the end of the holiday, we said a fond farewell. But two weeks later, I noticed three lumps where there shouldn’t be. I thought they would just go away but they didn’t so I went to see my GP who recommended I go to a genito-urinary clinic.

“I was so embarrassed when I was diagnosed with genital warts.

“I had treatment and they went away - but the thing is that this condition can recur, as it is a virus that stays in the body. If only I had thought about this before I jumped into bed with this man. It caused me a great deal of discomfort, I wish I had taken precautions.”

Rosemary has a stark warning for those of her generation who are willing to jump into bed without considering the risks.

“We were both intelligent, middle-class people and you just trust someone like you, don’t you? Now, when I meet men I am serious about, I always insist they use a condom.

“Women of my age have to take this seriously, because you are putting yourself at risk. When you sleep with a man - no matter how nice and middle-class - you are also effectively sleeping with all of their previous partners. Women of my age have to wake up and realise that it can happen to them.”

* Additional reporting: Charlotte Kemp - Daily Mail