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the 'cuddle chemical'

Blood and spit from Linda Geddes, seated, Nic Fleming, left, and 11 of their guests was tested for homone levels before and after the vows.

When Linda Geddes walked down the aisle on her big day, she had more than the normal stress associated with a wedding: She was also anxious about the needle that would soon be stuck into her arm.

Ms. Geddes and her groom-to-be, Nic Fleming, had decided to turn their marriage into a science experiment, taking blood samples from themselves and 11 guests - including me - before and after the vows. Scientists would check blood and spit for levels of various hormones, to see whether they went up or down in response to all the love in the air.

Most brides, it's fair to assume, would be worried about getting blood on her dress (or generally grossing out the wedding party). But Ms. Geddes, a journalist for London-based New Scientist magazine, is devoted to using her life in her work.

After she and Mr. Fleming became engaged, she had scientists check their compatibility. Two companies looked at six genes from her, her fiancé, and six of her male colleagues, to see which man had a genetic profile that was her "best" match. The test was based on evidence that dissimilar genes between a woman and her partner may lead to greater sexual attraction and healthier kids. The tests hinted that Ms. Geddes might be better off with someone else - which only went to show, she said, that science can't tell you everything about love. They also did not deter her from breaking out the test tubes and lab coats at her nuptials.

"It started off as a joke with the editor of New Scientist," Ms. Geddes says. "He was saying 'Oh, surely there must be an experiment you could do at your wedding.' Then I thought, what a cool thing."

So on their wedding day in July, with the sun shining down on the English country home they had chosen as their venue, guests clinked glasses on the lawn as Paul Zak, head of the Center for Neuroeconomics Studies at Claremont Graduate University in California, snapped on surgical gloves in the dining hall. One of the bridesmaids distracted the volunteers while Prof. Zak took a small vial of blood from each of us. After sipping Champagne as a balm, we took our seats for the vows. During the I dos, the bride and groom held hands and grinned with delight. Even Prof. Zak, who hadn't met them before, says he was "feeling the love."

Other than getting married, Ms. Geddes's main objective of the day was to see what would happen to her levels of oxytocin - a hormone also known as the "cuddle chemical" that is suspected to help create feelings of bonding, trust and empathy. The theory was that oxytocin levels would increase because of the vows. (While they were at it, the happy couple decided to throw in a few other tests, for testosterone and stress hormones.)

After the ceremony, it was time for yet more blood. The bride gamely held her arm out, as medical helpers clustered around. Nearby, the groom worked hard to build up enough spit to fill his sample jar. We all giggled at the absurdity of the day.

The result? The person with the biggest spike in oxytocin was the bride (up 28 per cent from before the wedding, which, according to Prof. Zak, is a lot). This fit nicely with the theory that the hormone is linked to feelings of bonding and empathy. Second was the bride's mother, followed by the father of the groom and the groom himself. Most of the friends tested experienced a small decline. The groom also had an unexpected surge in testosterone. "It has been suggested I was thinking about the honeymoon," Mr. Fleming says.

Of course, interesting as the findings are, the sample size was not large enough for any hard conclusions to be drawn. What's next is for scientists to do more real-life tests to try to pin down exactly how hormones affect people. "It has convinced me we have to get into the field. I'm dreaming up other places we can go besides weddings," Prof. Zak says.

As for Ms. Geddes, the latest news is that she is three months pregnant. Will there be more experiments in the couple's future? "There's nothing planned, but who knows," Ms. Geddes says.

Special to The Globe and Mail

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