Here's what is keeping men away from marriage

Washington DC: With the share of Americans ages 25-34 who are married dropping 13 percentage points from 2000 to 2014, sociologist Mark Regnerus blames it on "cheap sex."

According to Regnerus, "cheap sex" is an economic term meant to describe sex that has very little cost in terms of time or emotional investment, giving it little value, Fox News reported.

Basing his ideas, in part, on the work of British social theorist Anthony Giddens, Regnerus, in the book 'Cheap Sex: The Transformation of Men, Marriage, and Monogamy,' highlighted the "two overlapping (but distinctive) markets, one for sex and one for marriage, with a rather large territory in between comprised of significant relationships of varying commitment and duration."

In yesteryear, women generally made men wait until marriage to have sex, but now, with porn on-demand and greater reproductive freedom, sex is a commodity available at any time, which has left men with little motivation for marriage.

Regnerus also cited demographer Steven Ruggles' prediction that one of every three people in their 20s will never marry.

Moreover, he held cheap sex responsible for the decreasing education and employment rates among men as six percent more women than men in the 25-34 age group have a bachelor's degree. He backed this theory up with a quote from social psychologists Roy Baumeister and Kathleen Vohs, who study this phenomenon.

"Nowadays young men can skip the wearying detour of getting education and career prospects to qualify for sex," they wrote. "Sex has become free and easy. This is today's version of the opiate of the (male) masses."

"To plenty of women, it appears that men have a fear of commitment. But men, on average, are not afraid of commitment," Regnerus noted. "The story is that men are in the driver's seat in the marriage market and are optimally positioned to navigate it in a way that privileges their (sexual) interests and preferences. It need not even be conscious behaviour on their part."

In turn, he writes, this leads women to settle, entering into doomed or otherwise unsatisfying marriages.

Regnerus even pointed to 'Fifty Shades of Grey' to prove his point, saying, "I recognize that it is fiction. It's made up. But when you sell 100 million copies in two years, your narrative is resonating. There's something to it."

All of this, Regnerus concluded, means that as long as sex is so low cost for men, heterosexual women will have increasing difficulties finding a partner worth committing to.