Iran's president, Mahmoud Ahmadinejad, has urged girls to marry at 16 to help keep Satan at bay.
His call is another controversial, if implicit, rejection of his country's highly praised family planning policy that was sanctioned by senior Islamic clerics two decades ago.
Paying tribute this weekend to a gathering of charities helping young Iranians to wed, Mr Ahmadinejad proclaimed: "I think the best time for girls to get married is 16, 17 and 18 - that is, when they first bloom and are at the height of tender feelings."
The right age for boys, he opined, "is 19, 20 and 21".
Mr Ahmadinejad suggested that young people should not worry about chronic employment and housing problems that deter many Iranians from marrying until they are in their late 20s. Both drawbacks, he claimed, would be solved by the end of his second term as president in three years.
"If we manage to make marriage simple, we can push Satan thousands of light years away from ourselves," he declared.
Mr Ahmadinejad and some Iranian clerics encourage young people to wed to keep them from sin and temptation - euphemisms for pre-marital sex - and to increase Iran's Muslim population as a bulwark against aging western enemies.
The legal age for marriage in Iran is 13 for girls and 15 for boys, although girls need the consent of their father or paternal grandfather at whatever age they choose to tie the knot.
Increasingly, many Iranian women delay marriage until they have finished university. Young men, meanwhile, defer the big day until they have completed not only their education but also two years' compulsory military service.
And both sexes are reluctant to marry until they can afford a home.
The alternative, which is often unappealing to young people, is to move in with the parents-in-law while they save for a deposit on their own accommodation.
Following record birth rates in the wake of the 1979 Islamic revolution, Iran succeeded in cutting its population growth from an all-time high of 3.2 per cent in 1986 to around 1.2 per cent today, a rate similar to that of the United States.
But Mr Ahmadinejad has criticised Iran's advanced family-planning programme as an ungodly western import. Since coming to power in 2005, he has called for a baby boom to double Iran's population, which is already at 75 million, with a third of the population between the ages of 15 and 30.
Such calls have alarmed his critics who point out that Iran is already struggling with high inflation and unemployment.
In July, Mr Ahmadinejad inaugurated a new policy to encourage population growth with financial incentives for every new child born.
Four months earlier, he warned that, in 30 years, Iran would be stuck with an aging population just as the West has and the situation would be "dangerous". He insisted that Iranian "people want to have kids" and insisted that "God is there to nourish them".
In 2006, Mr Ahmadinejad suggested that women should work less and devote more time to their "main mission" of raising children. "I am against saying that two children are enough," he said at the time.
"Our country ... has the capacity for many children to grow in it."
His remarks echoed those of the late Ayatollah Khomeini, founder of the Islamic republic, who in the early 1980s as Iran was embroiled in a devastating war with Iraq, encouraged Iranians to have more children.
But when the bloodshed with Iraq ended in 1988 and the economy dived, Iran's ruling clerics realised that they would have difficulty reconciling the population explosion with the revolution's goals of social and economic development. They would have to provide jobs, housing, education and health care.
Ayatollah Khomeini gave his blessing to a progressive national family planning programme in 1989. His successor, Ayatollah Ali Khamenei, went further, issuing fatwas permitting contraception and even sterilisation. Mobile teams scoured remote areas offering free condoms as well as on-the-spot tubal ligations for women and vasectomies for men as Iran embraced family planning with public and unabashed determination.
Having no more than two children became a patriotic act and Iran became so strikingly successful in controlling population growth that the United Nations considered the Islamic republic as a model for other Muslim countries.
The Quran makes no specific mention of birth control, although the Prophet Mohammed is recorded as saying: "Marry and multiply, for I shall make a display of you before other nations on the Day of Judgment."
Advocates of family planning counter with other words from the Prophet: "The most gruelling trial is to have plenty of children with no adequate means."