When most of us are out looking for love – or perhaps something more casual – we likely aren’t considering how economics are affecting our most intimate decisions. But a new book by University of British Columbia economics professor Marina Adshade says economic forces likely influence us in more ways than we think.

In fact, she argues almost every decision and every outcome in matters of sex is better understood by thinking within an economic framework.

In her new book, Dollars And Sex: How Economics Influences Sex and Love, Adshade explores some of the surprising and often counterintuitive ways that dollars and cents can affect love and sex.

For example, Adshade discovered that shorter men tend to have younger wives. How can economics explain that? It’s fairly simple, she says, and comes down to supply and demand forces in the dating market.

“Taller men find it easier to marry early,” Adshade explained to CTV’s Canada AM. “Shorter men tend to marry when they’re older. That’s when they tend to be more established in their careers and making a slightly higher income. And that makes it possible for them to attract younger wives.”

Or how about this factoid: lesbians tend to earn an average of 13 per cent more than comparable heterosexual women. Turns out that’s due to long-held beliefs about “breadwinning.”

“There’s this lesbian wage gap,” says Adshade. “One of the reasons is that heterosexual women often anticipate marrying someone earning a higher income, and lesbian women don’t anticipate that.”

“They look ahead and anticipate taking care of themselves, and possibly even a lower-earning partner,” which perhaps drives them to push harder to move ahead in their careers, she says.

It’s not just larger cultural and economic forces that govern our choices, sometimes it comes down to simple personal finances. For example, beer prices. How do they affect our sexual practices? The explanation is pretty simple, Adshade says.

“In economics, we think of substitutes and complements. And beer is a complement with casual sex. So when the price of beer goes up, casual sex goes down. So higher prices make for a healthier sexual markets,” she says.

Adshade decided to turn to the economics of sex while trying to figure out how to keep her students awake during lectures, she says.

“I’ve been teaching students for a long time and we always teach students the same things: interest rates, inflation rates. And over the years, I thought, ‘There’s got to be a better way of getting students engage in learning economics’,” she says.

So in 2008, she launched an undergraduate course titled “Economics of Sex and Love.” Not surprisingly, it was instantly a huge hit.

“The first time I offered the course, it was a big room and the first week of classes, students were sitting on the floor because so many had come to see what the course was about,” she says.

That class led to a wildly popular blog in which Adshade explores how consumer psychology, marketing and microeconomics intersect with our search for love and sex.

Now, her book is reminding readers that there are often forces guiding them that they may not even be aware of, turning matters of the heart into matter of dollars and cents.