Dating websites like Tinder are banned in Iran, but about 350 unofficial dating websites are believed to exist. It relies on traditional matchmakers like Malakeh Mogadam, who has converted her home into a lonely hearts call centre.
There, an army of matchmakers in her front room answer phones that never stop ringing - mainly mothers across Tehran calling on behalf of their single sons.
Money and parental approval are two major hurdles that couples must overcome before they can tie the knot.
“There are some rules and limitations within families.
But we aren’t forbidden to hang out together,” says Ashkan Ghane, a 22-year-old psychology student. His mixed group of friends in north Tehran could easily hail from a trendy area of a Western capital.
The number of births per woman of child-bearing age has fallen from 7 in 1980 to 1.8 in 2014 - below Britain's fertility rate, for example, of 1.9.
Anything that brings young adults together in a controlled way, in line with Islamic principles, is welcome, especially as the regime has an official target to double Iran’s population to 150 million by 2050.