How did the family planning experts react to Theroux's questioning about the sizes of their own families?

The Bangladeshis returning from the family planning conference appeared to be quite sincere in their desire to influence their fellow countrymen to keep the population in check. But it is clear they consider fewer than five children to be small. Finally, when Theroux attempted to ask them if others would listen when their own families were so large, they abruptly ended the conversation, apparently uncomfortable with the questioning and unable to come up with satisfactory answers.