Outgoing UNFPA representative Arthur Erken commended Bangladesh's achievement in reducing population growth through a proactive family planning programme focused on grassroots levels.
The pro-poor family planning programme had made Bangladesh "a low fertility country" with a rate of 2.3 children per woman, he said.
"In terms of using family planning, there is a huge divide between the rich and poor in many countries. But in Bangladesh, the difference is very little," he recently told The Daily Star in an interview at the United Nations Population Fund (UNFPA) office in the capital.
Erken is to leave Dhaka late this month.
Summing up his six years' work in Bangladesh, the population expert said the country was going through a "rapid socio-cultural transformation" with the young people comprising the largest proportion of the total population.
"The number of youths will even increase as that group will for sometime grow up, until the 35 and below will be the largest group. They will determine the culture of Bangladesh, not their parents," he said.
Insisting that the Bangladesh today is utterly different from the Bangladesh that belonged to the previous generation, he said, "I can guarantee the child is being born today will never have more than one or two children."
He suggested that the grassroots door-to-door family planning programme, which started in the 70s, change its mindset and promote permanent or long-term acting methods of contraceptives.
"Suppose a woman has two children by the age of 25. She is capable of having more children for another 20 years," said Erken pointing out that instead of taking the regular pills the woman must opt for long acting methods that are safer and less expensive.
He, however, finds it weird that child marriage should prevail in society when development indicators like the economic growth, education, and infant and maternal mortality rates are "going to the right direction".
"Half of the girls are getting married by the age of 16," he said, observing that the age of marriage had not increased at all.
To him, the underlying reason for early marriage is dowry. "A girl who is older and educated is more expensive and requires more dowry than a younger, uneducated girl," said Erken.
The people of lower income brackets had a huge incentive to marry their daughters off quickly, he added.
Erken also pointed out that the issue of dowry had become more important in the last couple of decades. "It has become a prestige thing; people want to show that they can afford money," he said.
Birth registration, he suggested, could be a preventive tool which would help reduce child marriages to some extent.
"But the real change has to come from within the society," he observed.
In his opinion, opening up economic opportunities for girls will be effective because if a girl had a job and contributed to her family, the father would not want to marry her off so early.
Erken also suggested that policymakers prioritise making social services and safety networks available for all.