Registration officials in Iran supect there has been an increase of late in the number of informal and "unregistered" relationships. People are experimenting more with Western-style affairs of the heart, in other words — "shacking up" rather than rushing into marriage.

And they're not even going through the bother of entering a "temporary marriage," a legal loophole that exists in Iran for lovers who don't necessarily plan to make it a long-term thing. Last year, there were just 168 such arrangements nationwide, Ahmad Tuiserkani, head of the state registration body, told the daily Arman-e Emrooz.

Temporary marriages, to put it bluntly, allow couples to have sex without violating religious or cultural norms. They often serve the needs of bachelors or widows with money problems, divorcees, or anyone unable or unwilling to marry for good. Some critics call it "legitimate" prostitution as it usually involves payment of money to the wife.

Now, it seems, Iranian couples are dispensing with even that formality, instead dating and sleeping together like people elsewhere. Tuiserkani claims that the average lifespan of a couple in Iran is now "less than three years" and that 60% of the people who do marry lack a university education.

Shahla Kazemipur, a lecturer at Tehran University, sees the trend as logical given other changes taking place in Iranian society. "As society moves toward modernization, the marriage age goes up," she told the news agency ISNA.

Whereas men and women married at around 25 and 20 respectively in 1979, Kazemipur observed that they now tended to marry — in the proper, non "temporary" sense — at the ages of 27.5 and 23.4.