I may have misheard, but I'm pretty sure he just said that there are no homosexuals in Iran. "We don't have that phenomenon."
UPDATE: Here's what he said:
"In Iran, we don't have homosexuals like in your country. We don't have that in our country."
The audience booed and hissed loudly. Some laughed, uncomfortably.
"In Iran, we do not have this phenomenon," Mr. Ahmadinejad continued, undeterred. "I do not know who has told you that we have it..."