By Frances Harrison
BBC News, Tehran
Iran's Interior Minister, Mostafa Pour-Mohammadi, has started promoting temporary marriage as a solution to the country's social problems.
Unmarried Iranian couples can fall foul of strict Islamic morality laws
Shia Islam allows a man and woman to marry for a fixed period of time, ranging from an hour to a century.
A man can also have any number of temporary marriages - or sigheh, as they are known.
However, Iranian society still looks down on temporary marriage as a cover for prostitution.
Iran's interior minister, himself a cleric, said marriage was a human need and temporary marriage should not be used just for sex but to solve social problems.
He said there needed to be a cultural change to allow this.
He also said couples should marry at an earlier age.
Iran first started promoting temporary marriage as an alternative to living in sin 15 years ago.
The then President, Hashemi Rafsanjani, said it was a way for men and women to satisfy their sexual needs.
He even said there was no need for a cleric: the couple could read out an oath in private in order to marry.
Iran's police have recently cracked down on "un-Islamic" dress
These days, some girls who want to travel with their boyfriends and be allowed to stay in the same hotel room or avoid arrest by the moral police might have a temporary marriage.
Poor women who need financial support also do it.
But on the whole there is still a strong taboo against the practice.
One woman MP asked the interior minister if a man came to ask for the hand of his daughter in marriage, would he willingly tell him how many temporary marriages she had had.
Another warned that promoting temporary marriages would cause thousands of problems.
There are already tens of thousands of children from temporary marriages whose fathers will not acknowledge them and are therefore considered illegitimate.
One Friday prayer leader has suggested that Iran needs a centre to help young people find spouses.
Meanwhile, a hardline newspaper has complained that a travel agent in Tehran has been advertising holidays by the Caspian Sea for couples who want to have temporary marriages, offering accommodation and a cleric to register the marriage.